Method
Preheat the oven to 180C, gas 4. Grease a 22cm x 22cm cake tin with low calorie cooking spray and line with greaseproof paper.
Put the egg yolks and sweetener in a large bowl. Add the orange zest and juice. Using an electric whisk, beat for 5 minutes until pale and slightly thickened.
In a clean bowl, whisk the egg whites until soft peaks form. Gently fold into the egg yolk mixture. Sift the flour and baking powder into another bowl and gently fold into the eggs.
Spoon the mixture into the prepared tin and bake for 20-25 minutes or until golden and firm. Cool in the tin for 10 mins then turn out and cool completely.
For the topping, put the soft cheese, Quark, sugar and most of the orange zest into a bowl and stir well. Whisk briefly to create a smooth topping – take care not to over-beat or the mixture will be too loose. Spread evenly over the cake. Chill for 10 mins then sprinkle over the remaining orange zest, cut into 16 squares and top each one with raspberries.
You can bake and ice the cake in advance and keep it chilled for up to 3 days. Slice and decorate with raspberries when you’re ready to eat.
Credits : http://www.goodtoknow.co.uk/