Add 1/4 cup milk or as required, 1 tbsp sugar and a pinch of baking soda into the Marie biscuit powder and whisk well so that no lumps are left. The batter should be thick pouring consistency.

Now pour 1 layer of chocolate batter and one layer of Marie batter into the mug. Keep adding alternate layers till the cup is half-filled. Make the design of your choice using a toothpick.