In the second half of the dough, add the cocoa powder sifted through a sieve, the dough turns out tight, so you need to add a couple of spoonfuls of kefir, milk or yogurt that are at hand. Add the coarsely chopped nuts, mix, and then add the rest of the whipped whites. The consistency of the dark dough should be the same as that of the light one. If necessary, add another spoonful of kefir or milk.