Very important: Make sure all wet ingredients are at room temp so the batter mixes smoothly; otherwise, it can clump.
Preheat oven to 350°F. Generously spray all 12 cavities of a good quality muffin tin with cooking spray. Skip liners for this recipe (batter sticks)
Add bananas to a large bowl and beat with a hand mixer until smooth like applesauce. Measure to get 1 level cup and discard any excess. Add egg, coconut oil, honey, yogurt, and vanilla. Whisk until smooth and fully combined.
Sprinkle baking soda, baking powder, cinnamon, and salt on top and whisk to combine. Add flour and switch to a wooden spoon, gently mixing just until combined. Do not overmix. Divide batter evenly among 12 muffin cups, filling to the top.
Crumb Topping: In a bowl, stir together sugar, flour, cinnamon, and salt. Add melted (not hot) butter and stir until crumbly. Use your hands if needed to form crumbs. Sprinkle crumb topping evenly over all muffins, using all the mixture.
Bake 15–18 minutes, until a toothpick comes out clean or with a few moist crumbs. Cool in the pan 5 minutes, then transfer to a cooling rack to cool completely.
Video
Notes
Note 1: Use very ripe bananas with brown peels for the best flavor and sweetness.Storage: Let muffins cool completely, then store in an airtight container. Keep at room temp 1–2 days, in the fridge up to 4 days, or freeze up to 3 months.