Preheat the oven to 375 degrees F (190 degrees C). Lightly grease 10 muffin cups or line with paper liners.

Combine 1 ½ cups flour, baking soda, baking powder, and salt in a large bowl. Beat bananas, ⅓ cup melted butter, white sugar, and egg in separate bowl; stir into flour mixture just until moistened. Spoon batter into the prepared muffin cups.

Combine brown sugar, 2 tablespoons flour, and cinnamon in a small bowl; cut in 1 tablespoon butter with a fork until mixture resembles coarse cornmeal. Sprinkle over muffins.

Bake in the preheated oven until golden and tops spring back when lightly pressed, 18 to 20 minutes.