Preheat your oven to 350°F (175°C). In a mixing bowl, whisk together flour, baking powder, and salt. In another bowl, mix sugar, eggs, milk, and vanilla until smooth. Combine wet and dry ingredients, divide into pans, and bake for 25-30 minutes. Cool completely.

For the custard, heat milk until steaming. Whisk together egg yolks and sugar until pale. Temper the egg mixture with hot milk, then cook until thickened, about 8-10 minutes. Cool in the refrigerator.

Heat heavy cream until bubbling, pour over chopped chocolate, let sit a minute, then stir until smooth. Cool slightly.

Layer one cake on a plate, spread custard on top, place second layer over it, and pour ganache on top, allowing it to drape down the sides.

Refrigerate for at least 1 hour to set ganache. Serve chilled for the best flavor.