Preheat the oven to 180 C / 356 F.

Cover jelly pan with baking paper and spray it. Leave aside.

In medium sized bowl, combine dry ingredients: sugar, flour, baking powder and cocoa powder. Leave aside.

In another medium sized bowl, mix egg whites and pinch of salt until stiff peaks form.

Slowly add dry ingredients, water and egg yolks; gently combine with spatula.

Pour into prepared pan and bake for 8 minutes or until toothpick inserted in the middle comes out clean.

Leave to cool for two minutes and invert on a wet kitchen towel. Roll up th ecake in the towel, jelly roll style, starting with long side.

Cool completely.

While cake is cooling, prepare the filling: start with whipping cream to get stiff peaks and gently add the rest of the ingredients.

Unroll the cake and spread filling over it leaving ½ inch space edge. Roll up again.

Place seem side down on a serving platter. Cool in the fridge before serving.