30 g dark cocoa powder
40-50 g strong coffee
2 eggs
75 g sugar, including as much vanilla sugar as you like
100 g vegetable oil
125 g milk
150 g flour
1 1/2 ts baking powder
oven: 180 deg C, preheated; 45 min
pan: springform, 18 cm, bottom covered with parchment paper
Combine flour, baking powder and salt, set aside. In a mixing bowl, combine eggs and sugar. Whisk with a hand-held mixer until the mixture is creamy and pale. Add oil and milk, continue beating until well blended. Gradually add the flour mixture and stir just until smooth. Consistency of the batter should be liquidy.
Divide the batter into 2 equal portions. Stir the cocoa mixture into one portion until well blended.
Using a ladle that holds 3-4 tablespoons, pour alternately plain and dark batter into the middle of the baking pan. Work uninterruptedly - the batter will spread by itself and fill the pan gradually. Bake until golden brown (toothpick test).