¾ cup cake flour
¾ tsp baking powder
1 pinch salt
3 large egg whites
½ cup sugar
1 tsp vanilla extract
2 cups raspberries
2 cups blackberries
⅓ cup powdered sugar, plus extra for dusting
⅓ cup mascarpone
½ cup heavy cream, chilled
- Preheat oven to 350° F.
- Butter a large cake pan and line it with parchment paper, then grease parchment paper with butter.
- To make batter, sift flour, baking powder and salt together in a medium bowl. In a separate bowl, beat eggs until lightened in color and very thick. Add vanilla and sugar, and beat until combined.
- Gently fold flour mixture into the eggs, then mix at low speed until just incorporated.
- Pour batter into greased pan, smoothing the top, bake for 20 minutes, or until golden brown.
- Remove cake from oven, run a knife around the edges to loosen it from the pan, and let cool 5 minutes.
- Generously dust a clean dishtowel with powdered sugar and invert cake pan onto the dishtowel. Gently roll the warm cake up and set aside to cool.
- Sift powdered sugar into mascarpone and whisk together to combine. In a large bowl or mixer, whip heavy cream until stiff peaks form. Fold cream into mascarpone mixture, then fold berries into the cream.
- Carefully unroll cake and spread mascarpone and berry mixture evenly over the inside. Re-roll cake around the filling, ending with seam side facing down.
- Refrigerate until ready to serve, dust with powdered sugar before serving.