Mix the dry ingredients

• Add the flour, cocoa powder, sugar and salt to the mug.
• Stir with a whisk until evenly combined.

Add the wet ingredients

• Pour in the melted butter and milk.
• Crack in the egg and whisk until the batter is smooth and lump-free.

Add the chocolate

• Fold the chocolate chips through the batter.

Microwave the brownie

• Microwave on high until the top is set and slightly fudgy in the centre.

Rest and serve

• Let the brownie cool in the mug for a moment before eating.