Marble mug cake

1. Mix all ingredients except cocoa and 2 tablespoons of milk in a bowl with a whisk.
2. Divide the mixture into 2 parts. Mix cocoa mixed with milk into one part.
3. Pour the batter alternately with a spoon into the silicone cake mold, which you don't need to wipe with anything, a layer of white and a layer of dark dough. If we have a classic metal mold, grease it and sprinkle it with flour.
4. Bake at a temperature of 160-170°C for 40-45 minutes, depending on the type of oven.