Gather your ingredients, preheat the oven at 405F / 207C.
If using whole eggs, separate the whites
Add the oatmeal, sugar/sugar substitute to taste, pinch of salt, splash of vanilla extract (to taste) and baking powder.
TIP: If you want extra protein you can use less oatmeal and add a scoop of vanilla whey protein powder.
Whisk gently until it all comes together. TIP: the more you whisk it, the more they will grow in the oven. However, they most likely will deflate when cooled down.
Line your cupcake tin with baking cups. Then use a large spoon to fill the cups with the mixture.
Fill just the bottom of the cups at first.
Using a teaspoon add little chunks of peanut butter (I'm using homemade)
Then pour more dough mixture until you fill 3/4 of the cup.
Bake for 10 to 15 minutes at 405F / 207C or until golden brown