In a large mixing bowl, mash your bananas and add the applesauce and maple syrup. Mix well. Then add the flour, baking powder, baking soda, cinnamon, and mix until combined. Then fold in the chopped walnuts, if using them.
Scoop your mixture between 9 muffin tins. (Use nonstick, muffin liners, or grease if necessary.) Bake for 24-26 minutes, until a toothpick inserted in the middle comes out clean.
IMPORTANT: Let the muffins rest for 10-15 minutes in the pan before transferring to a wire rack. The muffins will be soft and delicate when fresh out of the oven, but they will firm up as they cool.
Notes
Use very ripe bananas! This recipe only calls for 2 tablespoons of maple syrup, so use overly ripe bananas with brown spots on the peels, for natural sweetness.
Weigh your flour. Scooping flour from a bag is less accurate than weight. So if you have a kitchen scale, use it for the best texture and results.
Use FRESH baking powder. Baking powder that has been open for over 6+ months may start to lose its effectiveness and rising power.
Individual ovens will vary, so bake until a toothpick inserted in the middle comes out dry and clean. Mine were perfect in 24 minutes.
Keep leftovers in a sealed container or tightly wrapped at room temperature for 1-2 days. Refrigerate them for up to 5 days, or freeze them airtight for up to 3 months.