Delicious marble cake

Margarine, stir smooth. Sugar, vanilla and salt, stir among them. Add the eggs one by one. Stir flour with baking powder and milk. 2 / 3 of batter into the greased pan. Cocoa and milk among the remaining batter and stir. The dark dough, spread it over the Hellen and draw a spiral with a fork through the dough. Bake at 180 degrees C (convection oven 160 degrees) about 60 minutes.