A one-person brownie mug cake made by mixing flour, cocoa, sugar, baking powder, salt, milk, oil, and vanilla directly in a microwave-safe mug, then microwaving until the top is set but the middle stays moist.
Mix the Dry Ingredients. In a microwave-safe mug, whisk together 1/4 cup flour, 2 tbsp cocoa powder, 2 tbsp sugar, 1/4 tsp baking powder, and a pinch of salt.
Add Wet Ingredients. Stir in 1/4 cup milk, 2 tbsp vegetable oil, and 1/4 tsp vanilla extract until smooth. Be sure to mix all the ingredients thoroughly, scraping the bottom and sides of the mug.
Microwave. Place the mug in the microwave and cook on high for 1 minute to 1 minute 15 seconds. The brownie should rise and be set on top but still moist in the center.
Add Toppings. For an extra treat, sprinkle chocolate chips on top or add a scoop of vanilla ice cream. Enjoy your brownie straight out of the mug while it's still warm!