Directions

1. Preheat oven to 180 °C (350 °F).
2. Line a tin (~25 × 35 cm) with baking paper.
3. Lightly dust a second sheet of baking paper with cocoa powder — you’ll flip the sponge onto this later.
4. In a bowl, beat egg yolks, coconut sugar, and vanilla until pale and thick (2–3 mins).
5. In a separate clean bowl, whisk egg whites + salt to stiff peaks.
6. Sift together cocoa + collagen powder.
7. Gently fold dry mixture into yolks, then stir in 1 tbsp milk to loosen.
8. Fold in the whipped whites in 2–3 additions, keeping it light and airy.
9. Spread the batter evenly in the tin.
10. Bake 10–12 minutes, until just set and springy to touch (internal temp ~90–93 °C).

11. Roll while still warm

12. Flip the sponge onto your cocoa-dusted paper.
13. Carefully peel off the baking paper it baked on.
14. Roll gently (with the cocoa paper inside) to form the roulade shape.
15. Cool fully (20 mins).
16. Unroll gently. Spread the Greek yoghurt protein filling evenly.
17. Roll back up tightly, using the paper to help guide it.
18. Chill 20–30 mins to set. ( I recommend using the freezer here)
19. Dust with cocoa powder or top with shaved dark chocolate.
20. Serve as is or with stewed cherries or raspberries.