Steps
In a microwave-safe mug, mix the flour, cocoa powder, sugar, baking powder, instant coffee, and salt until well combined.
Add the milk, vegetable oil, and vanilla extract to the dry ingredients and stir until smooth.
Microwave on high for 1 minute and 30 seconds, or until the cake has risen and is set in the center.
Let it cool for a minute before enjoying straight from the mug.