50g (1 ¾ oz) cocoa powder, sifted
20g (3/4 oz) white chocolate, to decorate
For the filling:
250g (9 oz) 0% fat Greek yogurt
3 tsp icing sugar, sifted
½ tsp vanilla extract
125g (4 ½ oz) fresh raspberries (reserve a few to decorate)
Instructions
- Preheat the oven to Gas Mark 4/ 180⁰C/fan 160⁰C. Line an 18cm x 28cm (7in x 11 in) swiss roll tin with baking parchment, snipping the corners of the paper to make a tight fit.
- Use an electric hand whisk or food mixer to beat the egg yolks and sugar for about 5 minutes or until pale and thick. Fold in the cocoa powder.
- Whisk the egg whites in a clean, dry bowl until they form stiff peaks. Add 1-2 tbsp of the egg whites to the egg yolk mixture to loosen it, then gradually fold in the rest of the egg whites until thoroughly combined.
- Pour the mixture into the prepared tin and bake for 25 minutes until risen and springy to the touch. Leave in the tin for 5 minutes, then invert on to a clean piece of parchment paper, dusted lightly with ½ tsp of the icing sugar.,When cool peel away the base layer of paper.