Banana Bread Muffins

1 stick softened butter
1 cup sugar
2 eggs, beaten
4 bananas, finely mashed
1 1/2 C. flour
1 tsp. baking soda
1/2 tsp. salt
1/2 tsp. vanilla

Mix well. Bake at 350*, 60 minutes for a loaf and about 20 minutes for muffins.