01 -
Switch the oven on to 350°F (175°C). Place parchment paper at the base of an 8x8-inch pan.
02 -
Combine softened butter, eggs, flour, baking powder, salt, ½ cup sugar, and a teaspoon of vanilla in a mixing bowl. Stir everything together until it's smooth.
03 -
Transfer the batter into your prepared pan. Pop it into the oven for 20-25 minutes. It's done when a toothpick inserted into the middle comes out clean. Let it cool all the way down.
04 -
Warm up milk and ½ cup sugar in a saucepan over medium heat. Stir until the sugar's dissolved and the milk mixture is steamy but not boiling.
05 -
In a separate bowl, whisk egg yolks and cornstarch until smooth. Gradually add the steamy milk mixture, a bit at a time, while constantly whisking. Pour it all back into the saucepan and cook on medium heat, stirring all the time, until thick. Once done, remove from heat and mix in 2 tablespoons butter and 1 teaspoon vanilla.
06 -
Spread the custard over the cooled cake. Put it in the fridge to set completely.
07 -
Heat cream in a small pot until it just starts to bubble. Take it off the heat and pour over the chopped dark chocolate. Let it sit for a couple of minutes before stirring until smooth.
08 -
Drizzle the ganache on top of the custard layer. Refrigerate at least 2 hours or until the ganache firms up.
09 -
Slice into squares and serve cold.