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Dark Chocolate Mousse Cake with Chocolate Mirror Glaze

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A chocolate lovers dream cake! Dark Chocolate Mousse Cake with a decadent Chocolate Mirror Glaze. With three different layers of chocolate, this is sure to be your new go-to cake for any and all special occasions! Picture a delicious and fudge-y chocolate espresso cake layer, topped with a thick layer of luscious chocolate mousse, and finished with a homemade and silky smooth chocolate mirror glaze. This cake is one that everyone is sure to love! Serve at any and all special occasions, from birthday’s, to get-togethers/parties, and even holiday’s. So. GOOD.

angled shot of sliced chocolate mousse cake with another slice beside on stack of two plates, a cake knife and bowl of chocolate curls beside, white flowers and cheese cloth behind.

About The Recipe

To me, there is no such thing as too much chocolate. This recipe is pretty much everything I love all baked into one cake! I mean, three layers of rich and decadent chocolate? COUNT ME IN!

Plus, it looks super fancy and highly impressive, but requires minimal effort when it comes to decoration.

This cake was actually inspired by our S’mores Icebox Cake! We fell in LOVE with how easy chocolate mousse was to make and knew we needed to incorporate it into more recipes.

Though, we wanted to try and do something a little more upscale, you know?

So, we started thinking. We’ve shared chocolate mousse, mousse ice cream, cream puffs filled with mousse, a mousse pie, an icebox cake…we’ve kind of done it all. Well, we realized that we hadn’t done a cake!

And, I mean, is there really anything better than a slice of cake?

slice of chocolate mousse cake on white plate with fork beside and mousse cake behind.

Okay, so. We knew we wanted a chocolate cake with our mousse…now what?

Well, my mom and I both watch Great British Baking Show a lot and one of the things we see the contestants make often is a mirror glaze. It always looks like fun and we thought this cake would be the perfect excuse to finally try and make our own!

Which means…we have the components of the cake! Now, time for test baking. Thankfully, the cake and the mousse were a BREEZE!

The mirror glaze is what took us a while.

slice of mousse cake being lifted from cake on upside down white plate with another slice in front.

It took my mom and I days to finally get a mirror glaze recipe that would work. There was always something weird going on. Too much gelatin, too little gelatin, too many bubbles, not shiny enough…the list goes on.

On the third day, we finally got everything just right!

So, we poured it over the cake with bated breath and…we had a perfect mirror glaze! Like, it was so shiny that I could see myself, which made taking pictures of this cake kinda funny (if you see my face in the cake, sorry!).

The best part, though? The final recipe for the mirror glaze was our easiest concoction yet!

So, while there are a lot of moving parts to this recipe, it is, in actuality, not too hard to make! Which makes it the perfect cake for any and every occasion. That, and it just tastes REALLY good!!

Reasons You Will Love This Chocolate Mousse Cake

  • A chocolate lovers DREAM!
  • Three layers of chocolate-y deliciousness.
  • Rich, not too sweet, and melts in your mouth.
  • The perfect make-ahead dessert for any occasion.
  • Crowd pleasing!
  • No fuss decoration.
  • Simply stunning to look at and oh so impressive.
slice of chocolate mousse cake with forkful of cake beside.

Equipment Needed

Ingredients

(Full ingredient amounts and instructions can be found in the recipe card at the bottom of the post)

For The Cake:

cocoa powder, flour, vegetable oil, egg, baking powder, sugar, salt, espresso powder, water, heavy cream, vanilla, and baking soda on marble surface.

For The Mousse:

  • Heavy Cream
  • Dark Chocolate Pieces
  • Powdered Gelatin
  • Water
  • Large Eggs
  • Egg Yolks
  • Granulated Sugar
chocolate chips, sugar, cream, eggs, water, and gelatin on marble surface

For The Mirror Glaze:

corn syrup, water, sugar, cocoa powder, gelatin, and heavy cream on marble surface.

How To Make Chocolate Mousse Cake

Step 1: Make the cake

In a small bowl, combine cocoa, espresso powder, and water. Whisk until smooth. Set aside.

In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.

Add the egg, milk, oil, and vanilla. Mix well.

Stir in the chocolate mixture.

Pour into prepared pan. Bake for 25 minutes, or until done.

Step 2: Make the mousse

Whip cream to stiff peaks. Refrigerate until needed.

In a small bowl, dissolve gelatin in water. Set aside.

Whisk together eggs, egg yolks, and sugar in a medium bowl.

Place over simmering water. Heat, while whisking, to 135° F. Remove from the heat.

Stir in gelatin. Whip with an electric mixer until light and fluffy, about 3-4 minutes.

Microwave chocolate in 15 second increments, stirring after each, until melted and smooth.

melted chocolate on marble surface in glass bowl

Stir into egg mixture.

Fold whipped cream into chocolate mixture, ⅓ at a time.

Step 3: Assemble cake

Turn cooled cake out onto wire cooling rack. Trim to level the cake layer. Place in a plastic wrap lined cake pan. Top with mousse. Cover and refrigerate overnight or until set.

Step 4: Make mirror glaze

In a small bowl, dissolve gelatin in 2½ Tablespoons water. Set aside.

In a small saucepan, combine sugar and ¼ cup water. Heat and stir over medium heat until sugar is dissolved.

Stir in corn syrup and cocoa powder.

Mix in the cream.

Return to heat. Cook and stir over medium heat until mixture reaches 190 °F. Remove from heat. Allow to cool to between 130 °F and 140 °F.

cooked chocolate mixture in large pot.

Stir in gelatin. Continue stirring until melted and smooth.

Strain into a glass bowl. Use a rubber spatula to stir gently until all the streaks are gone. Allow to cool to 80 °F.

Transfer into a measuring cup.

chocolate mirror glaze in 2 cup measure.

Step 5: Finish cake

Remove cake from the fridge and lift out of pan. Place on a cooling rack lined sheet pan and, using an offset spatula, smooth the sides of the mousse.

In slow circling motions, pour the mirror glaze onto the cake, starting from the middle and working your way outwards. Allow to set up before serving, about 5-10 minutes.

Decorating Ideas

This cake is so simple and elegant that when it comes to decorating, it doesn’t need much! Though, there are a few fun things to really make this cake even more gorgeous. Just be sure to keep it minimal as that mirror glaze really is the star of the show!

  • Decorated with edible gold leaf.
  • Chocolate whip cream (or Chantilly Cream!) piped around the edges.
  • Chocolate curls!
  • Flicked with melted white chocolate.
  • Edible flowers.
  • Drizzled with Caramel Sauce.

How To Store Chocolate Mousse Cake

Once this cake is made and the mirror glaze is set, this recipe can be kept in the refrigerator for 2-4 days or frozen for up to 2 months! Though, the cake itself can be made ahead of time and frozen as an individual layer. Then, when needed, you can top with mousse and keep that in the fridge for about 2 days before you need to finish it with the mirror glaze and enjoy! Just keep in mind that his cake needs to be covered and kept in the fridge, as it is very moist.

Another note, once refrigerated or frozen, the mirror glaze will lose it’s shine.

Looking for more recipes like this? Here are a few you may like: Ultimate Chocolate Layer Cake, German Chocolate Cake, Molten Lava Cakes, Chocolate Mousse Filled Cream Puffs, Chocolate Soufflé

mousse cake with slice on stack of two white plates in front, white flowers and chocolate curls around, stack of white plates, and glass of utensils behind.

Expert Tips

  • You can boil the water in a microwave, on the stove top, or in a kettle!
  • Mixing the boiling water, cocoa powder, and espresso powder is a technique called, “blooming”. This allows for the powder to dissolve and release all of it’s amazing flavors. That means you wind up with a much more flavorful and delicious cake!
  • Be sure to check the expiration dates on your baking powder and baking soda
  • Use a cake tester or a toothpick to test when this cake is done.
  • When making the chocolate mousse, be sure that the gelatin is entirely dissolved into the egg mixture before moving forward. You don’t want chunks of gelatin in your mousse!
  • The melted chocolate NEEDS to be warm for this recipe. If it gets cold by the time you add it to the egg mixture, you will have chunks of chocolate in your mousse.
  • Be careful to not over-whip your cream!
  • When folding in the whipped cream, do not over fold. You don’t want to deflate the mousse.
  • Do NOT boil the mirror glaze or over-mix it! Be as gentle with it as you can.
  • Once the mirror glaze is poured onto the cake, this is the time to move it! Place it on any cake plate or serving platter you wish to have it on to serve.
  • Try and keep the mirror glaze as thin as possible! It’s not the most pleasant thing to bite into if there’s a large quantity.
  • You can use an offset spatula to help move/thin the mirror glaze once it’s on the cake.
  • If there are bubbles in your mirror glaze, no worries! Once the glaze is set, use a heated offset spatula to smoothen out any imperfections.

When you make this Dark Chocolate Mousse Cake with Chocolate Mirror Glaze, leave a comment down below! We love hearing from you and answering any questions you might have! Also, be sure to tag us on social media and hashtag it #BakersTable.

angled shot of sliced chocolate mousse cake with another slice beside on stack of two plates, a cake knife and bowl of chocolate curls beside, white flowers and cheese cloth behind.
4.84 from 6 votes

Dark Chocolate Mousse Cake with Chocolate Mirror Glaze

A chocolate lovers dream cake! With three layers of luscious chocolate, there's really no better dessert than this Dark Chocolate Mousse Cake with Chocolate Mirror Glaze. Every bite is rich, extra chocolate-y, and so good.
Prep Time: 45 minutes
Cook Time: 1 hour
Refrigeration Time 12 hours
Total Time: 13 hours 45 minutes
Servings: 8

Ingredients
 

Cake

  • cup natural process cocoa powder
  • 1 teaspoon espresso powder
  • 6 Tablespoons boiling water
  • ¾ cup all purpose flour*
  • cup granulated sugar
  • 1 teaspoon baking powder
  • ¼ teaspoon baking soda
  • teaspoon salt
  • 1 large egg, room temperature
  • 6 Tablespoons whole milk
  • 3 Tablespoons vegetable oil
  • ¾ teaspoon vanilla extract

Mousse

  • 2 cups heavy cream, cold
  • 1⅓ cups dark chocolate pieces
  • teaspoons powdered gelatin
  • 2 Tablespoons water
  • 2 large eggs
  • 2 large egg yolks
  • 3 Tablespoons granulated sugar

Mirror Glaze

  • teaspoons powdered gelatin
  • Tablespoons water
  • 6 Tablespoons granulated sugar
  • ¼ cup water
  • 1 Tablespoon corn syrup
  • cup natural process cocoa powder
  • ¼ cup heavy cream

Instructions
 

Cake

  • Heat oven to 350℉.
  • Spray an 8 inch round pan with baking spray.
  • In a small bowl, combine cocoa, espresso powder, and water.
  • Whisk until smooth. Set aside.
  • In a large bowl, whisk together flour, sugar, baking powder, baking soda, and salt.
  • Add egg, milk, oil, and vanilla.
  • Mix well.
  • Add chocolate mixture.
  • Mix only to blend.
  • Pour into prepared pan.
  • Bake for 25 minutes, or until done.

Mousse

  • Whip cream to stiff peaks.
  • Refrigerate until needed.
  • In a small bowl, dissolve gelatin in water. Set aside.
  • In a medium bowl, whisk together eggs, egg yolks, and sugar.
  • Set bowl over a pot of simmering water.
  • Cook, whisking constantly, until mixture reaches 135℉.
  • Remove bowl from heat.
  • Stir in gelatin.
  • Beat with an electric mixer until mixture is light and fluffy, about 3-4 minutes.
  • Place chocolate in a medium-sized microwave safe bowl.
  • Heat on high in 15 second increments, stirring well after each, until chocolate is melted and smooth.
  • Stir into egg mixture.
  • Fold whipped cream into chocolate mixture, ⅓ at a time.

Putting It Together

  • Turn cooled cake out of pan.
  • Trim to level.
  • Line 8 inch round pan with plastic wrap.
  • Place cake layer in pan.
  • Top with mousse.
  • Cover and refrigerate overnight or until set.
  • Smooth sides of mousse with an offset spatula before glazing.

Mirror Glaze

  • In a small bowl, dissolve gelatin in 2½ Tablespoons water. Set aside.
  • In a small saucepan, combine sugar and ¼ cup water.
  • Heat and stir over medium heat until sugar is dissolved.
  • Remove from heat.
  • Stir in corn syrup and cocoa powder.
  • Mix in cream.
  • Return to heat.
  • Cook and stir over medium heat until mixture reaches 190℉.
  • Remove from heat.
  • Allow to cool to between 130℉ and 140℉.
  • Stir in gelatin.
  • Continue stirring until melted and smooth.
  • Strain into a glass bowl.
  • Use a rubber spatula to stir gently until all the streaks are gone.
  • Allow to cool to 80℉.
  • Immediately pour over cake.

Notes + Tips!

*This recipe was written using an average of the dip and sweep method for measuring flour and the spoon and level method. If you are using a scale, you will need to add 3/4 oz or 22 g  to the measurement for each cup of flour.
  • You can boil the water in a microwave, on the stove top, or in a kettle!
  • Mixing the boiling water, cocoa powder, and espresso powder is a technique called, “blooming”. This allows for the powder to dissolve and release all of it’s amazing flavors. That means you wind up with a much more flavorful and delicious cake!
  • Be sure to check the expiration dates on your baking powder and baking soda.
  • Use a cake tester or a toothpick to test when this cake is done.
  • When making the chocolate mousse, be sure that the gelatin is entirely dissolved into the egg mixture before moving forward. You don’t want chunks of gelatin in your mousse!
  • The melted chocolate NEEDS to be warm for this recipe. If it gets cold by the time you add it to the egg mixture, you will have chunks of chocolate in your mousse.
  • Be careful to not over whip your cream!
  • When folding in the whipped cream, do not over fold. You don’t want to deflate the mousse.
  • Do NOT boil the mirror glaze or over-mix it! Be as gentle with it as you can.
  • Once the mirror glaze is poured onto the cake, this is the time to move it! Place it on any cake plate or serving platter you wish to have it on to serve.
  • Try and keep the mirror glaze as thin as possible! It’s not the most pleasant thing to bite into if there’s a large quantity.
  • You can use an offset spatula to help move/thin the mirror glaze once it’s on the cake.
  • If there are bubbles in your mirror glaze, no worries! Once the glaze is set, use a heated offset spatula to smoothen out any imperfections.

Nutrition

Serving: 1slice | Calories: 672kcal | Carbohydrates: 65g | Protein: 12g | Fat: 43g | Saturated Fat: 27g | Polyunsaturated Fat: 5g | Monounsaturated Fat: 9g | Trans Fat: 0.04g | Cholesterol: 193mg | Sodium: 275mg | Potassium: 428mg | Fiber: 4g | Sugar: 45g | Vitamin A: 1168IU | Vitamin C: 1mg | Calcium: 208mg | Iron: 3mg

Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.

When you make this recipe, remember to tag @bakerstble or hashtag it #BakersTable!

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4 Comments

  1. 5 stars
    This is a new favorite in my family! Its not too rich or overly sweet which is perfect! The mirror glaze really elevates it! Delicious.

    1. Hi Ali! We’re so happy to hear everyone loved this cake and that it turned out well! 🥰 We hope you find more recipes that you and your family love on our blog 🫶 x, Caylie

  2. 4 stars
    My family LOVED this cake! Now I’m trying variations with different flavored mousse, thanks so much for sharing your recipe.