Preheat oven to 350°F (175°C). Grease two round cake pans and dust with flour.

In a bowl, whisk together flour, sugar, baking powder, and salt. In another bowl, beat butter, eggs, and milk until smooth. Gradually combine wet and dry ingredients without overmixing.

Pour batter evenly into prepared pans and bake for 25-30 minutes until golden; let cool completely.

For pastry cream, heat milk and vanilla in a saucepan. Whisk egg yolks with sugar; gradually add hot milk while whisking. Return to heat until thickened.

Assemble by layering one cake with pastry cream and topping with the second layer.

For ganache, heat heavy cream until simmering; pour over chocolate chips and stir until smooth. Pour over assembled cake.