Preheat oven to 400 degrees F. Spray ten cups of a muffin tin with cooking spray.
Stir together mashed bananas, oil, egg, milk, and sugar. Stir in baking mix and oats just until combined. Scoop muffin dough evenly into prepared ten muffin cups.
Use the backside of a round tablespoon measuring spoon to make an indentation in the top of each muffin. Spoon about a teaspoon of peanut butter and a teaspoon of jelly into the center of each muffin.
Bake in preheated oven for 15 minutes or until top edges are brown. Allow to cool in pan for a few minutes, and then carefully lift each muffin onto a cooling rack. (Don’t dump the muffins out or the tops will get messed up.) Filling will be hot, so allow to cool to a safe temperature before serving.