Preheat oven to 350 F. Grease muffin pans or line with cupcake liners.

Mix together butter and sugar until creamy. Beat in egg and vanilla.

Mix in mashed banana and sour cream until well blended.

Add flour, baking soda, salt and cinnamon until well combined.

Stir in 1/2 cup chocolate chips.

Use a cookie scoop to spoon batter into prepared muffin cups, greased or paper liners. Fill almost to the top. This will make for nice rounded tops. Sprinkle with remaining chocolate chips.

Bake at 350 for about 18-22 minutes or until toothpick inserted in the center comes out clean. Cool on a wire rack.