Place chocolate pieces and cream in a small microwave-safe bowl.
Microwave in 30 second intervals, stirring after each, until chocolate is melted and smooth.
Pour chocolate mixture into a 2 quart baking dish.
Cover with a piece of plastic wrap, making sure it touches the surface of the chocolate.
Refrigerate until firm, about an hour.
Remove from refrigerator and, using a small cookie scoop, scoop ganache into balls and place on a parchment-lined sheet pan.
Preheat oven to 350 degrees.
Spray 8 six ounce ramekins with baking spray. Set aside.
Combine chocolate pieces and butter in a microwave-safe bowl.
Microwave in 30 second intervals, stirring after each, until both chocolate and butter are melted and smooth. Set aside.
In a large bowl, whisk together eggs, sugar, and vanilla.
Beat in cooled chocolate mixture.
Gently stir in flour.
Fill each ramekin half full.
Place a frozen plug of ganache on each and press down slightly.
Cover with remaining batter.
Place on a sheet tray and place in the oven.
Bake for 12-15 minutes, until cake is just starting to pull away from the edges of the ramekin.
Remove from oven.
Invert gently onto plate.
You can leave the ganache in the fridge overnight.
Use a high quality chocolate for this recipe.
Don't over mix the batter!
If you leave the cakes to cool slightly in the ramekins and they stuck, use a thin knife and gently push down in the gap between the cake and the ramekin. Try and keep the knife as close to the ramekin as possible because you don't want to poke the cake! Also, don't slide the knife around the ramekin. Gently poke around the edges until the cake is loose.
These cakes are very fragile! Once you turn them out, try not to move them.
If you don't have ramekins, you can bake these cakes in coffee mugs or mini cocottes!