Preheat your oven to 350°F (180°C). In a large mixing bowl, whisk together the cake flour, baking powder, and salt until combined.

In another bowl, beat the room temperature eggs, sugar, milk, and vanilla extract until smooth and creamy.

Fold the wet ingredients into the dry mixture until just combined. Pour evenly into two greased 9-inch round cake pans.

Bake for 25 to 30 minutes until golden brown and a toothpick inserted in the center comes out clean.

Allow the cakes to cool in the pans for 10 minutes, then transfer to a wire rack to cool completely.

In a saucepan over medium heat, warm the milk until it begins to steam but does not boil.

In a separate bowl, whisk together the egg yolks and sugar until pale and creamy.

Gradually pour the hot milk into the egg mixture while whisking. Return the mixture to the saucepan and cook over low heat, stirring constantly, until thickened, about 8-10 minutes.

Remove from heat and let cool.

Heat the heavy cream in a small saucepan until it just begins to bubble.

Pour it over the chopped semi-sweet chocolate in a mixing bowl and let sit for a minute to soften before stirring until smooth.

Place one chilled cake layer on a serving plate and spread the cooled custard over the top.

Carefully place the second cake layer on top of the custard and pour the warm ganache over the assembled cake.

Refrigerate the pie for at least one hour to let everything set before slicing.

Slice the chilled pie neatly with a sharp knife and serve with a dollop of whipped cream or a drizzle of chocolate sauce if desired.