Heat the oven to 180°C. Using Frylight, grease then line a square baking tin.
Mix together the egg yolks, sweetener, cocoa powder and vanilla extract. If the batter is too thick, gradually add some water, tablespoon by tablespoon.
In a separate dish, whisk the egg whites until soft peaks are formed.
Add a spoonful of the whites to your chocolate mixture and gently fold it in. Gradually, keep adding the whites and gently fold them until well combined.
Pour into your cake mould and bake for 30 minutes. Remove from the tin and let cool completely.
Meanwhile, make the frosting. Mix all ingredients together until well combined. Refrigerate until ready to use, then spread on the cooled down cake. Cut into 16 squares and top with fresh raspberries.