For the dough, mix the flour with baking soda and baking powder and sift into a mixing bowl. Add sugar, vanilla sugar, eggs, butter or margarine and cream.
Process the ingredients for 2 minutes using a hand mixer with a whisk on the highest setting to form a smooth dough.
Pour half of the dough into a loaf pan (25x11cm, greased, dusted with flour). Stir cocoa, cinnamon and milk into the rest of the batter.
Spread the dark dough on the light dough. Pull a fork through the layers of dough in a spiral to create a marble pattern. Put the tin on the wire rack in the oven.
E-stove: about 180 ° (preheated)
Circulating air: about 160 ° (not preheated)
Gas: level 2-3 (not preheated)
Baking time: about 60 minutes
Let the cake stand in the mold for 10 minutes after baking, then remove it from the mold and let it cool on a baking rack lined with baking paper.