Step 1

Preheat the oven to 350°F (175°C). Grease and flour two 9-inch round cake pans.

Step 2

In a medium bowl, whisk together the flour, baking powder, and salt.

Step 3

In a large bowl, beat the butter and sugar together until light and fluffy. Add eggs one at a time, beating well after each addition. Stir in vanilla.

Step 4

Alternately add dry ingredients and milk to the butter mixture, starting and ending with dry ingredients. Mix until just combined.

Step 5

Divide the batter evenly between the prepared pans. Bake for 25-30 minutes, or until a toothpick inserted into the center comes out clean. Allow to cool in pans for 10 minutes, then turn out onto a wire rack to cool completely.

Step 6

In a medium saucepan, combine milk, sugar, and salt and bring to a simmer over medium heat. In a separate bowl, whisk together cornstarch and egg yolks.

Step 7

Temper the yolks by slowly pouring some of the hot milk into the yolks while whisking constantly. Return the yolk mixture to the saucepan. Cook over medium heat, stirring constantly, until the mixture thickens and comes to a boil. Remove from heat and stir in vanilla.

Step 8

Transfer to a bowl and cover with plastic wrap directly on the surface to prevent a skin from forming. Chill in the refrigerator until set.

Step 9

Heat the heavy cream in a small saucepan until it begins to simmer. Remove from heat and add the chopped chocolate and corn syrup, letting sit for a few minutes. Stir until smooth.

Step 10

Place one cake layer on a serving plate. Spread the custard evenly over the top. Top with the second cake layer.

Step 11

Pour the chocolate glaze over the top of the cake, allowing some to drip down the sides.

Step 12

Chill the assembled cake in the refrigerator for at least 1 hour to set the glaze and firm up the custard.

Step 13

Slice and serve chilled.