Combine flour, powdered sugar, almond flour, and baking powder in the bowl of a food processor.
Process until combined, about 1 minute.
Add butter slices, pulsing after each, until combined.
With processor running, add egg and yolk.
Process until a smooth dough forms.
Turn dough out onto a piece of parchment paper.
Roll into a circle that is 1/4" thick.
Fit into tart pan.
Press dough to fit.
Using edge of pan, remove excess dough.
Cover pan with plastic wrap.
Refrigerate for at least 30 minutes.
While crust is chilling, heat oven to 350 degrees F.
Bake for 12-15 minutes, until just starting to lightly brown.
Remove from oven and set aside to cool.
Pastry Cream
In a medium bowl, combine sugar, corn starch, and egg yolks.
Stir with a wooden spoon or a rubber spatula until combined. Do NOT beat. Set aside.
In a saucepan, heat milk until it is starting to bubble around the edges.
Stirring constantly, add a small amount of hot milk to egg mixture.
Continue to add small amounts of hot milk to egg mixture while stirring until about half is used.
Add egg mixture to sauce pan with the rest of the hot milk.
Return to heat and whisk until thickened, about 2 minutes.
Remove from heat, and whisk in white chocolate, butter, and matcha.
Pour into cooled tart shell.
Refrigerate.
Notes
Expert Tips:
Be sure to sift the matcha!
If the dough rips when you're putting it into the pan, it okay! This can easily be fixed. Gently press it back together and it should be okay.
When the custard starts to thicken, don't panic! Let it keep cooking for about 2 minutes afterwards. It should be very thick before stirring in the white chocolate.
Make sure you get the white chocolate, butter, and matcha completely incorporated!
If the custard is a little lumpy, run it through a very fine meshed sieve.
The crust doesn't need to be overly browned. Just lightly browned. Keep an eye on it while it bakes!
Make sure your tart pan has a removable bottom!
Excess dough can be wrapped in plastic, placed in a zip top bag, and frozen for later use.