The sweetness of these muffins will depend on the sweetness of your bananas, the type of peanut butter you use and how much maple syrup you add. We like our muffins lightly sweet, so I add half a cup of maple syrup but use peanut butter that is only one ingredient (peanuts!) If you use peanut butter that has added sugar, your muffins will turn out a bit sweeter. Also remember to adjust your cooking times if you use mini or a jumbo muffin pans. Store muffins on the counter in an airtight container - or freeze! Thaw overnight in the refrigerator.
In a large bowl or in your stand mixer, cream butter, Greek yogurt and maple syrup until smooth. Stir in egg, vanilla and peanut butter and stir until well combined.
In a second bowl, whisk flour, baking powder, baking soda and salt until combined.
Add slowly add flour mixture to the creamed ingredients. Fold in mashed bananas.
Spoon batter into a standard-sized, oiled or lined muffin pan, filling 3/4 full.
Bake for 16-18 minutes or until a toothpick comes out clean.
If you would like an extra special treat, melt a few chocolate chips in the microwave by adding them to a safe bowl, and microwave at 50% power for 45 seconds, mix with a spoon and continue cooking in 30 second increments and stirring until the mixture is melted and smooth. Use a small spoon to drizzle zig zags across the muffins. Or in the case of my house, spoon a little chocolate on top, give the spoon over to the 4 year old and let her have fun! She decorated the cupcakes in the pictures. :)