Banana Crumb Muffins with Cinnamon Topping

Ingredients

• 1-1/2 cups all-purpose flour
• 1 teaspoon baking soda
• 1 teaspoon baking powder
• 1/2 teaspoon salt
• 3 large ripe bananas, mashed
• 3/4 cup sugar
• 1 egg, lightly beaten
• 1/2 cup butter, melted
• TOPPING:
• 1/3 cup packed brown sugar
• 1 tablespoon all-purpose flour
• 1/8 teaspoon ground cinnamon
• 1 tablespoon cold butter