In 12-ounce microwave-safe ceramic mug add flour, sugar, cocoa powder, and baking powder. Stir with a fork to combine ingredients.
Add chocolate chips, peanut butter, milk, vegetable oil, vanilla, and salt. Stir to combine everything together well. Wipe the top of the mug clean, if desired.
Microwave on high for about 60-90 seconds, depending on the power of your microwave.Allow cake to cool before adding whipped topping and/or berries.