In a stand mixer with paddle attachment, mash up bananas. Add sugar applesauce(or oil), & eggs. Mix well. Scrape bowl.
Add flour, baking powder, baking soda, cinnamon, & nutmeg all at once. Mix until just blended.
Spray or line muffin tins with paper cups. Fill each cup ⅔ full. Combine streusel ingredients in a separate bowl & mash with a fork until crumbly. Sprinkle topping over each muffin. Bake at 350*F for 20-25 minutes until muffins spring back when touched.
*Recipe can be made into 1 loaf; bake at 350*F for 45 min-1 hour.