Instructions

1. 1

   Grease a small loaf tin about 20 cm long with the butter or margarine and stand it in the basket while it is still empty to check the clearance. Only if air is left all round does the heat sweep past the tin and the cake brown evenly.

2. 2

   Mix the plain flour with the sugar, the vanilla sugar, the baking powder and the salt in a bowl. Combined dry, the baking powder is spread evenly everywhere.

3. 3

   Add the eggs, the milk and the rapeseed oil and stir everything to a smooth batter. Do not stir longer than necessary, or the cake turns tough instead of fluffy.

4. 4

   Put a third of the batter in a second bowl and stir it smooth with the cocoa powder and the tablespoon of milk. The tablespoon of milk makes up for the liquid the cocoa powder soaks up.

5. 5

   Pour the pale batter into the tin, spoon the dark batter on top and draw a fork through both in wide loops. Drawing for too long blurs the marbling into an even brown.

6. 6

   Preheat the airfryer to 160 °C, because at a higher heat the surface is dark before the middle is done.

7. 7

   Stand the tin centrally in the basket in a single layer and stack nothing on top; only one tin fits in, so a larger quantity is baked in two runs. Bake at 160 °C.

8. 8

   Turn the tin by half a turn so that the back gets just as much heat, and insert a wooden skewer into the middle; in a loaf tin the cake stands higher than in a shallow tin and needs a little longer. If batter still clings to it, carry on baking at 160 °C until the skewer stays dry.

9. 9

   Leave the cake to cool in the tin before you loosen it from the sides with a knife and turn it out.