Preheat your oven to 180 degrees Celsius.
In a large bowl, whisk the eggs and granulated sweetener with an electric whisk for about 2-3 minutes until doubled in size. If doing by hand, it will take a bit longer.
In a small bowl, mix the flour, baking powder and cocoa powder.
Gently fold the dry ingredients into the wet ingredients until the batter is smooth.
Spray a cake tin well with 1kcal spray and pour the mixture in.
Bake for about 20 minutes until just firm on top (and a knife comes out clean).
Remove from the tin and allow cool.
Carefully slice the cake down the middle horizontally.
Whip the cream.
Crush the thawed frozen raspberries slightly and spread over one half of the cake.
Top with the whipped cream.
Carefully place the other half of the cake on top.
Dust with icing sugar (optional) and decorate with a spare raspberry.