Preheat the oven to 390°F. Cut the bananas into pieces and put them in a bowl along with brown sugar and oil. Mash well with a fork until creamy (if a few pieces of banana will remain it will be okay).

In another bowl mix together flour, salt and baking soda. Combine the dry ingredients to the wet ones, also add two tablespoons of chocolate chips. Stir using a spoon just until you no longer see flour lumps.

Pour the batter into muffin cups (you can use both paper cups placed in metal molds or silicone molds, if you prefer). Top the muffins with a few chocolate chips.

Bake for 5 minutes at 390°F, then lower the temperature to 350°F and bake 15 minutes more. After this time check the muffins with a toothpick (if you use silicone molds you need to bake a few minutes more).