Spray a mug or large ramekin with cooking spray.

In a bowl, mash the banana with a fork. Add the oats, egg whites, salt, peanut butter, vanilla, and cinnamon. Mix well, then fold in the chocolate chips.

Divide the batter evenly across the number of servings shown in the recipe details (for example, if your recipe calls for 2 muffins, split the batter between 2 mugs or ramekins). Leave some room at the top as muffins will expand during cooking.

Microwave each muffin on high for about 2 minutes or until the muffin is set and the top is firm to the touch.

Let cool slightly, then run a butter knife around the edges to loosen the muffin before transferring it to a plate.

Repeat with any remaining servings.

Meal Prep Tip: Store muffins individually wrapped in plastic in the fridge for up to 1 week. Reheat briefly in the microwave before eating.