Heat oven to 176c or (350° Fahrenheit). Line muffin cups with paper liners. This recipe makes 12 regular-sized muffins.

Whisk the flour, brown sugar, baking powder, baking soda, and salt in a large bowl.

In a separate bowl, whisk the melted butter, mashed banana, egg, and vanilla until blended.

Add the banana mixture to the bowl with dry ingredients, then use a fork to combine. Do not overmix.

Stir in the chocolate chips

Fill muffin cups 3/4 full. Bake until a toothpick can be inserted and comes out clean, 20 to 25 minutes.