How to make
First, beat the eggs until whitened. Without stopping beating, subsequently add the sugar, oil, milk, the flour mixed with the baking powder and the orange zest.
Set aside a small part of the cake mixture, mix it with 1 tbsp cocoa. Alternate between the 2 mixtures in an oiled and floured form. Bake about 1 hour in a 360°F (180 °C) oven.