Classic Boston Cream Pie Recipe

In a medium bowl, whisk together the egg (or egg yolks), sugar, cornstarch and salt aggressively for 1-2 minutes, until the mixture becomes smooth and runny, with no more chunks.
5 large egg yolks room temperature, 100 grams granulated sugar scant cup, 42 grams cornstarch, tiny pinch fine sea salt
In a medium saucepan, heat the milk and cream over medium heat, just until it comes to a simmer.
240 mL whole milk, 120 mL heavy cream
Temper the eggs by streaming half of the milk into the egg mixture while continuing to whisk.
Dump the whole mixture back into the saucepan and cook over medium-low heat, while whisking continuously.
Within 1-3 minutes, the mixture should start to thicken, continue whisking, making sure to scrape the edges and center of the pan.
Once it's starting to stick to the pan, whisk aggressively for another 30-60 seconds. Remove from the heat and pour into a bowl with the butter and vanilla.
2 tsp vanilla bean paste or extract, 56 grams salted butter room temperature
Allow the heat from the pastry cream to melt the butter for a second and then gently whisk it. It may separate at first but it'll come back together as you whisk.
The pastry cream should be smooth and silky now, if you have any lumps, feel free to push it though a sieve.

Preheat the oven to 350F/177C convection and grease and line one deep 8 inch cake pan with baking spray and parchment paper *see note if you don't have a deep pan*
Place the flour, baking powder and sea salt in a medium bowl and whisk them together until they’re evenly distributed.
240 grams all-purpose flour spooned and leveled, 2 tsp baking powder, 1/2 tsp fine sea salt
Place the milk with the butter in a small pot and heat it gently over medium-low heat, for 2-3 minutes, just until the butter is fully melted and the mixture is hot but not yet simmering. Remove from the heat and set aside.
240 mL milk, 113 grams salted butter gets melted with milk
Place the eggs in the bowl of a stand mixer, fit with the whisk attachment, and begin beating at medium-high speed, until the eggs begin to froth , just a few seconds. Reduce the speed and stream in the sugar.
4 large eggs room temperature, 350 grams granulated sugar
Add the vanilla extract and turn the mixer up to full speed, allowing it to beat for a few minutes, until the sugar and egg mixture is fluffy and pale.
2 tsp vanilla extract
Sift the dry ingredients over the egg mixture, and now turn the mixer up to low speed while streaming in the milk and butter. Scrape the edge of the bowl and give it one more mix, just until the last streak of flour is combined.
Pour the batter into the prepared pan and bake for about 45 minutes, until it's a dark golden brown and releases from the edge of the pan.

Place the cream in a small saucepan over medium heat and bring heat until it’s steaming/simmering but not boiling.
175 grams heavy whipping cream cold
Place the chocolate in a medium bowl and pour over the hot cream on top of the chocolate.
175 grams dark chocolate chopped
Cover the bowl and let sit 1–2 minutes and then stir slowly from the center outward until the ganache is smooth and glossy.
Let it rest at room temperature until it's completely set and spreadable.

Once the cake, pastry cream and chocolate ganache have cooled, slice the cake in half and place the bottom layer of the cake onto a flat surface.
Spread the pastry cream on top of the bottom layer of cake and then place the top layer of cake on the pastry cream. At this point I like to chill the cake for 15-30 minutes to make sure it's sturdy.
Gently spread the chocolate ganache on top of the cake and sprinkle with a pinch of flakey sea salt.
tiny pinch flakey sea salt