Banana Blueberry Muffins

3 ripe bananas 3/4 c sugar 1 egg 1/3 cup melted butter 1 c blueberries 1 tsp baking soda 1 tsp baking powder 1/2 tsp salt 1 1/2 c flour Mash bananas in a large mixing bowl. Add sugar and egg. Add butter and blueberries. Combine dry ingredients and gently stir into banana mixture. Pour into 12 well-greased muffin cups. Bake at 375 degrees for 20 min.