Pour in � cup of milk, � cup of all-purpose flour and � teaspoon of baking powder in a mug. Whisk until the mixture is smooth.
Add in � cup of Nutella and continue to whisk until the batter has no lumps.
Microwave the cake for about 45-60 seconds till the cake looks set and dry but also fluffy to the touch.
Optional: Top it off with whipped cream or powdered sugar.