First, beat eggs with powdered sugar until creamy. Add flour, milk, oil and baking powder and mix for about 4 minutes until fluffy.
Grease a cake pan and sprinkle with flour. Pour in half of the mixture.
Stir cocoa powder into the other half and spread over the light mixture.
Mix a little with a fork and bake the Gugelhupf in the oven at 180 °C top/bottom heat for approx. 45 minutes.