Step 1

Spray the inside of a microwave-safe mug with non-stick cooking spray (be liberal about it!).

Step 2

Crack an egg into the mug, add the brownie mix, fill the remaining space in the mug with whipped cream- about 1/2-2/3 of a cup.

Step 3

Mix with a fork until completely blended. Add a generous dollop of peanut butter to the batter, about a rounded tablespoon.

Step 4

Microwave on high for 1 minute, 10 seconds.

Step 5

Remove from microwave and immediately invert the cake onto a serving dish.