Preheat the oven to 350°F (175°C) and prepare two round cake pans with butter and parchment paper.

In a mixing bowl, beat together the butter and sugar until fluffy. Add eggs one at a time, then mix in flour, baking powder, and milk until combined.

Divide the batter evenly between the prepared pans and bake for 25-30 minutes or until a toothpick comes out clean. Cool for ten minutes before transferring to wire racks.

For the custard filling, whisk together whole milk, cornstarch, sugar, and vanilla in a saucepan over medium heat until thickened. Let cool slightly before using.

Slice each cooled cake layer in half horizontally. Layer custard filling between the slices.

For the glaze, heat heavy cream until simmering; pour over chocolate chips and stir until smooth. Drizzle over the assembled cake.