Here's the recipe I usually prepare:
Choco Banana Muffins
1 1/2 cups of all purpose flour
1 tsp baking soda
1 tsp baking powder
1/2 teaspoon salt
3 large ripe bananas, mashed*
3/4 cup sugar
1 large egg well beaten
1/3 cup melted butter
80 gms. choco chips
* I don't finely mash the bananas since hubby likes to eat some tiny chunks of it. But if you like yours smooth and less chunkier, finely mash the bananas then.
Pre-heat oven to 190 degrees. Slightly spray a 12-cup muffin pan with cooking spray.
In a large bowl, combined all dry muffin ingredients (except for sugar). In another bowl, combine the bananas, sugar, egg and melter butter; mix well. Stir into the dry ingredients, only until moistened. Do not over mixed or else your muffins will come out a bit tough. Fill the muffin cups 3/4 cup full.
Bake for 18-20 mins or until the muffins test done. Cool in pan for 10 mins before removing to a wire rack.