1In a microwave-safe mug, whisk together the all-purpose flour, cocoa powder, sugar, baking powder, and salt until well combined.
Add the milk, vegetable oil, and vanilla extract to the dry ingredients and stir until smooth and well mixed.
Microwave the mug on high for 1 minute and 30 seconds to 2 minutes, or until the cake has risen and is set in the middle.
Allow the mug cake to cool for a few minutes before enjoying.