Easy Banana Blueberry Muffins

taken and adapted slightly from geniuskitchen.com

3 large bananas
1/3 c. sugar
1 egg
1/4-1/3 c. melted butter
1 c. blueberries (or raspberries, etc.)
1 tsp baking soda
1 tsp baking powder
1/2 tsp salt
1 1/2 c. flour

Mash bananas in bowl.  Add sugar and egg.  Add butter and blueberries.  Add dry ingredients and stir gently.  Pour into greased muffin tins.  Bake at 375 for 18-20 min.