Banana Chocolate Chip Muffins

1/2 c butter
1 c sugar
2 eggs
1 c mashed bananas (3 small, 2 med)
1 1/3 c flour
1 t soda
1/2 t baking powder
1/2 t salt
3/4 c choc chips

Mash bananas. Add ingredients in order listed. Bake at 350 for 15-20 mins.