Scratch Boston Cream Pie

Ingredients

• 1.5 teaspoons double-acting baking powder 
• 3 tablespoons butter 
• 1.5 cups cake flour (6.8 oz)
• 1 tablespoon plus 
• 1 oz cupcake liners 
• 4 large egg yolk 
• 3 large eggs at room temperature
• 1 oz flour well
• 0.7 cup granulated sugar 
• 0.3 cup cup heavy whipping cream 
• 0.3 teaspoon butter salted (Reduce to a pinch of using butter)
• 4 oz bittersweet chocolate chopped
• 1 teaspoon vanilla extract 
• 2 cups milk whole

Equipment

• bowl
• frying pan
• baking sheet
• sauce pan
• oven
• knife
• whisk
• mixing bowl
• blender
• stand mixer
• microwave
• springform pan
• measuring cup

Directions

1. Preheat oven to 350 degrees F. Grease the bottom of a 9 inch round springform pan and line bottom with a round of parchment. Leave sides ungreased.In the bowl of a stand mixer, beat the eggs for 3 minutes. Gradually add sugar and beat for 10 minutes longer. Meanwhile, sift together the flour and the baking powder and set aside.
2. Combine the butter, milk, and salt in a large glass measuring cup or saucepan and heat just until mixture boils and butter is melted
3. Add the vanilla extract and set aside.With mixer on low speed or by hand, mix the flour mixture into the whipped egg mixture.
4. Remove 2 cups of this mixture and put it in a smaller mixing bowl, then stir in the hot milk mixture.
5. Add it all back to the main mixing bowl and beat on low or medium low until smooth.
6. Pour the batter into the pan, set the pan on a baking sheet and bake for about 45 minutes or until cake springs back when touched. Run a knife around sides of pan to loosen and let cool for about a half hour in the pan.
7. Remove sides of springform and let cool completely. Split cake horizontally and fill with pastry cream.
8. Place the milk and half of the sugar in a medium saucepan and bring to a gentle boil.While you’re waiting for the milk mixture to come to heat, whisk the remaining sugar into the egg yolks until thick and pale.
9. Combine the flour and cornstarch in a small cup or bowl, then whisk the flour/starch mixture into the egg/sugar mixture.When the milk comes to a boil, whisk a cup of hot milk into the egg mixture to temper and thin, then pour it all into the saucepan, whisking constantly. The pastry cream will thicken almost immediately. Continue to cook and stir until 1 or 2 large bubbles break the surface (this might take a minute or two, but it helps kill the enzymes that cause thinning).
10. Remove from the heat and whisk in the butter and vanilla.
11. Transfer the pastry cream to a clean container. Press a piece of parchment to the surface and let cool to room temperature.For the glaze combine 1/3 cup of heavy cream and 1 tablespoon of corn syrup in a 2 cup glass measuring cup.
12. Heat in the microwave for about 30 seconds or until the cream is very hot, then stirred in 4 oz of chopped semisweet chocolate. Stir until smooth and creamy. At this point it will be kind of thin, so let it cool down to a slightly thicker consistency and spoon over the cake.