|unsalted butter 82% fat - softened
|CACAO IN POLVERE
Whip all the ingredients together, except for the cocoa, in a planetary mixer with the whisk attachment at medium speed for 6 minutes.
Divide the mixture in two equal parts, add the cocoa to one of them and stir to perfectly combine it to the mixture.
Butter and flour the cake moulds. Pour the 'white' mixture and the cocoa flavoured mixtured into the prepared moulds in an irregular way, in order to produce a perfect marble-effect.
You can replace butter with margarine in the same dose."