Sieve the flour, cocoa powder, Cornflour, salt together. Keep aside. Remove 1 tbsp out of the sugar and keep aside too.
Whisk the eggs, yolks, sugar and vanilla extract together until it is pasty and falls back like ribbon.
Add the flour mix in 2 parts into the egg mixture, fold it in.
Now whisk the egg whites with the 1 tbsp of sugar, till it reaches firm peaks. Mix this into the flour mix.
Bake this for 6-7 minutes in a preheated oven or microwave oven (convection mode) at 220 degree Celsius. Sprinkle icing sugar on the sponge after it is removed immediately.
Pour this into a rectangular tin (43 cm × 30 cm) lined with butter paper.
Invert it on another sheet of butter paper and remove the bottom lining. Roll the sponge cake along with the paper and
cover it with a foil, leave it to cool.
Now for the filling, whisk butter until soft, add the sugar and whisk until fluffy. Add the vanilla, cream and the colour. Give it a mix.
Once the cake is cold, spread the icing on it and roll it. Chill and cut into pieces.