Pre-heat your oven to 375 degrees F and prepare a muffin tin by greasing it or using paper liners.
In a large bowl combine flour, baking soda, baking powder, and salt. Set aside.
In a small bowl combine mashed bananas, sugar, egg, and melted butter.
Combine the wet ingredients into the dry and stir lightly until combined.
Fold in chocolate chips.
In a small bowl combine brown sugar, flour, and ground cinnamon. Use a fork to mix in the butter until you have a crumbly mixture.
Spoon ¼ cup of muffin dough into each muffin cup. This should yield 12 muffins.
Divide the crumb topping mixture among the 12 muffins (about 1 teaspoon per muffin)
Bake for 18-22 minutes, or until a toothpick inserted into the center comes out clean.
Allow to cool for a few minutes, then serve.