In a large bowl add the egg yolks and ¾ cup sugar. Beat with an electric mixer until the mixture becomes lighter in color and thicker. Add in the cornstarch and continue to mix until well combined.
Meanwhile, add 2 cups of milk to a medium saucepan. Scald it by heating it on medium heat until small bubbles start appearing around the walls of the saucepan. Remove the saucepan from the heat at that point.
Whisk ¼ cup of the scalded milk into the bowl with the egg mixture until combined, then whisk in the remaining scalded milk. Pour the mixture back into the saucepan and cook it over medium-low heat, whisking constantly, until it starts to boil. Continue whisking it for about a minute after it begins boiling until it becomes as thick as a pudding.
Remove the pan from the heat and stir in 1 tablespoon butter, 1 teaspoon vanilla extract, and 1 tablespoon brandy. Let cool for about 15 minutes, then cover it with plastic wrap, pressing the plastic against the surface so a skin doesn't form. Chill in the refrigerator while you bake the cake.
Preheat the oven to 350 F. Grease two 8-inch round pans and line the bottoms of the pans with parchment paper.
In a large bowl whisk together the flour, baking powder and salt. Set aside.
In the bowl of a stand mixer add the 3 eggs and remaining 1½ cups granulated sugar. Beat until pale and fluffy. Melt the remaining 7 tablespoons of butter in the microwave, then add that to the bowl. Add in the remaining ½ cup milk, ⅓ cup orange juice, 1½ teaspoon vanilla extract, and 1 tablespoon brandy. Beat until combined.
Slowly add the flour mixture into the bowl with the wet ingredients, beat until just combined. Divide the batter evenly between the 2 prepared cake pans. Bake in the preheated oven for 25–30 minutes, until a toothpick inserted in the center of the cakes comes out clean. Let cool completely.
In a small bowl add the chopped chocolate, heavy cream and corn syrup. Heat in the microwave in 30 second intervals, stirring between each interval, until the chocolate is melted and the mixture is smooth.
To assemble, place one cake flat on a plate, spread the chilled pastry cream over the top of the cake. Place the second cake on top of the pastry cream. Pour the ganache over the top of the second cake, spread it to the edges and allow it to drip over the sides of the cake. Leave the drips down the side of the cake, or for a more polished look run a knife around the edges of the cake so the ganache covers the sides of the cake. Place the cake in the fridge and allow it to set for at least an hour before cutting and serving it.