In the mixer, beat the sugar with the butter until it forms a whitish mixture.
Gradually add the eggs and continue beating on medium speed. Add the flour and milk
Finally, add the vanilla, salt and yeast and beat.
Separate half of the dough in a bowl and add the cocoa powder, mix well
Apply parchment paper to the form. Start by adding about 3 tablespoons of the white mass and 3 spoons of the chocolate mass, repeat the process until all the mass is finished.