Start by taking a microwave-safe mug that holds about 8 oz of liquid.
Mix together 4 tbsp of flour, 4 tbsp of sugar, 2 tbsp of cocoa powder, 1/8 tsp of baking powder, and a pinch of salt.
Next, pour in 3 tbsp of milk, 2 tbsp of vegetable oil (or melted butter), and 1/4 tsp of vanilla extract.
Put the mug in the microwave and heat it on high for about 1 minute.
After microwaving, let the cake cool for a minute before you dig in—it's worth the wait!
Top your mug cake with whipped cream, some chocolate syrup, or a sprinkle of powdered sugar.