Preheat the oven to 350°F (175°C).

In a mixing bowl, combine the flour, sugar, baking powder, and salt.

Add the softened butter and mix on medium speed until light and fluffy.

Incorporate the eggs one at a time, mixing well after each addition, followed by the vanilla extract.

Gradually add the milk and mix until just combined.

Divide the batter evenly between the prepared cake pans.

Bake for about 25-30 minutes or until a toothpick inserted in the center comes out clean.

In a saucepan, heat the milk and sugar over medium heat until steaming.

In a bowl, whisk the egg yolks and cornstarch, then slowly add the hot milk mixture.

Return the mixture to the saucepan and cook, stirring constantly until thickened.

Remove from heat and stir in vanilla and butter.

Allow the cakes and custard to cool completely before assembling.

Once cooled, layer the custard between the cakes and top with warmed chocolate glaze.