01 -
Set the oven to 350°F (175°C). Line an 8x8-inch baking pan with parchment paper.
02 -
In a bowl, mix flour, ½ cup sugar, baking powder, and salt. Add softened butter, eggs, and 1 teaspoon vanilla extract. Beat until smooth.
03 -
Pour the batter into the prepared pan and bake for 20-25 minutes, or until a toothpick inserted into the center comes out clean. Let it cool completely.
04 -
In a saucepan, heat milk and ½ cup sugar over medium heat until the sugar dissolves and the mixture is hot but not boiling.
05 -
In a separate bowl, whisk cornstarch and egg yolks until smooth. Gradually pour the hot milk mixture into the egg mixture, whisking constantly. Return to the saucepan and cook over medium heat, stirring constantly, until it thickens and boils. Remove from heat and stir in 2 tablespoons butter and 1 teaspoon vanilla extract.
06 -
Pour the custard over the cooled cake base and refrigerate until set.
07 -
Heat heavy cream in a small saucepan until it begins to simmer. Remove from heat and pour over the chopped dark chocolate. Let sit for 2-3 minutes, then whisk until smooth.
08 -
Pour the ganache over the set custard layer and refrigerate for at least 2 hours, or until the ganache is firm.
09 -
Cut into squares and serve chilled.