Combine the milk, cream, and half of the sugar in a medium sauce pan over medium-high heat, stirring occasionally until the liquid comes to a simmer.

As the liquid heats, whisk together the remaining sugar, salt, cornstarch, and egg yolks in a medium bowl until light and creamy.

Once the milk mixture is hot, slowly whisk about 1 cup of the liquid into the egg mixture to temper the yolks. Pour the tempered egg mixture back into the saucepan with the hot milk mixture and reduce the heat to medium, continuing to cook while whisking constantly, until thickened and a few bubbled burst on the surface, about 30 seconds, although it might take a bit longer if your liquid wasn't as warm initially. If it hasn't thickened, continue to cook and stir until it does because it will not thicken in the fridge.

Remove the pastry cream from the heat and whisk in the butter and vanilla. If you are concerned about possibly having scrambled the eggs at all, you can press your pastry cream through a fine mesh sieve just in case.

Transfer the pastry cream to a bowl and cover with a sheet of plastic wrap placed directly onto the surface of the pastry cream so a skin doesn't form. Refrigerate until chilled, about 3-4 hours.

Preheat the oven to 325 degrees F. Line two 9-inch round cake pans with parchment paper circles and spray the sides with baking spray. Whisk the flour, baking powder, and salt together in a bowl and set aside.

Heat the milk and butter in a small saucepan over low heat until the butter is melted. Remove from the heat and stir in the vanilla.

In the bowl of a stand mixer fitted with the whisk attachment, beat the eggs and sugar for 4-5 minutes until light, airy, and thick.

Whisk in the hot milk and butter until combined.

Add the flour mixture, pulsing just until combined to form a fairly thin batter. Divide evenly between the two cake pans.

Bake for 20 to 25 minutes until a toothpick inserted into the center of the cakes comes out clean and the tops of the cake are a nice golden brown.

Cool completely in the cake pans before assembling the cake.

When it's almost time to assemble the cake, make the glaze by heating the heavy cream and corn syrup in a microwave safe bowl in the microwave for 60 seconds until very hot.

Pour the hot cream and corn syrup over the chopped chocolate in another bowl and let it sit for 1 minute. Stir until combined and smooth and glossy. Let this sit for about 5 minutes, stirring occasionally, until the ganache has thickened slightly.

Remove the cooled cake layers from the cake pans and peel off the parchment paper. Set one layer on a cake stand or cake plate, then cover with the pastry cream, spreading it almost all the way to the edges of the cake.

Add the second cake layer turned upside down for a nice flat top.

Pour the chocolate ganache over the top of the cake and gently spread it toward the edges, nudging it ever so slightly over the edge in some places to create beautiful drips of chocolate.

Transfer the finished cake to the refrigerator for at least 3 hours to chill and set up completely before slicing and serving.