Step 1: Mash the Banana

In a microwave-safe mug, mash the ripe banana with a fork until smooth. You want it to be mashed well to ensure it blends evenly with the other ingredients.

Step 2: Add the Wet Ingredients

To the mashed banana, add the melted butter (or oil), milk, and vanilla extract. Stir to combine everything together until the mixture is smooth.

Step 3: Add the Dry Ingredients

Add the flour, brown sugar, baking powder, and a pinch of salt to the mug. Stir until everything is well incorporated and there are no lumps. If you’re adding any mix-ins like chocolate chips or nuts, now’s the time to fold them in.

Step 4: Microwave the Mug Cake

Place the mug in the microwave and cook on high for 1 minute and 30 seconds. If the cake isn’t quite set in the center, microwave for an additional 15-30 seconds, checking every 10 seconds. Be careful not to overcook, as it will continue to cook in the mug once you remove it.

Step 5: Let It Cool

Let the mug cake cool down a bit before digging in—although it’s tempting to eat it straight away! It’s best enjoyed warm.