3.In another bowl, make the frosting by whisking together the cocoa powder and powdered sugar. Then add the butter, vanilla, and milk. Blend with a mixture until smooth. Add additional milk if needed to make the frosting spreadable.
4.Now it’s time to assemble the cake. With a serrated knife, cut off the domed top of each of the rounds to make the cake even and level. Save the parts you cut off for another use. Place one round on your serving platter or cake plate. Top with half of the filling mixture and spread evenly. Top with the other cake round.