Prepare the batter- Grease a large, microwave-safe mug. Place your dry ingredients into it and mix well. Add your eno, milk and mix until a smooth batter remains. If desired, fold through some chocolate chips.

Microwave the batter- Microwave your mug protein cake for 60 seconds, or up to 2 minutes. Cooking time depends on your brand of microwave.

Remove from the mug and enjoy- Allow your mug brownie to sit for 20 seconds, before slipping out of the mug onto a plate.