Mix the dry ingredients

• Combine the flour, sugar, cocoa powder and baking powder in a mixing bowl.

Add the wet ingredients

• Stir in the milk, oil and beaten egg until smooth.
• Fold in the Nutella until evenly combined.

Fill the mug

• Pour the batter into a large mug, filling it no more than two-thirds full.

Microwave

• Cook on high power until the cake has risen and the top is just set.

Rest and serve

• Let the mug cake rest briefly before eating.