Line a 9 inch/ 24-25 cm spring form pan with a circle of baking paper. Grease well inside the pan.
In a small bowl combine flour and salt and set aside.
In a large bowl beat the egg yolks with the two kinds of sugar, whiskey and vanilla until thick. Wash the beaters and dry them with a towel.
In another bowl beat the egg whites for about 5 minutes, until thick.
Using a rubber spatula, gradually add the dry ingredients to the egg yolk mixture. Mix gently until absorbed. Carefully fold in the egg whites.
Pour the batter into the prepared pan and bake for 40-45 minutes or until a toothpick inserted in the center comes out clean. Remove the pan from the oven and let cool for 10 minutes. Transfer the cake to a wire rack to cool completely.
In a small saucepan over medium heat combine milk, cornstarch and flour and whisk. Bring to boil while whisking continuously to avoid burning. When the mixture becomes thick, remove the pan from heat and let it cool to room temperature.
In a large mixing bowl beat together butter, vanilla and sugar until fluffy. Little by little add the cooled milk mixture and continue beating until it is absorbed in the butter. The consistency of the frosting should be creamy and fluffy.
Add the mascarpone cheese and continue beating until well combined.
Assemble the cake:
Using a serrated knife cut the cake base horizontally in two equal layers.
In a small bowl combine 3-4 tbs of the frosting and the cocoa powder. Mix well until the cocoa powder is completely absorbed. Let stay in the fridge while arranging the cake. This part of the frosting will be used for decoration.
Place one layer on a serving plate and cover it evenly with 2-3 tbs of the white frosting. Arrange the profiteroles on top of the frosting in order to fill the whole cake. Add more frosting on top of the profiteroles so that they are completely covered. Place the second cake layer over the frosting.
Frost the cake all around with the remaining frosting.
Decorate with chocolate sprinkles and cocoa frosting.
If your flour is not self raising, add 1,5 teaspoons baking powder together with the salt.
You can use store-bought profiteroles or you can make them on your own with this recipe.