This one is from my sister-in-law, Elizabeth Earl. It's a Mrs. Field's recipe.
3/4 cup butter/marg
1 1/2 cups light brown sugar
2 large eggs
3 cups mashed bananas (about 7 bananas)
1 tsp. vanilla
2 1/2 cups all purpose flour
1 1/2 tsp. baking soda
1/2 tsp. salt
1 cup chopped walnuts, optional
Cream butter and sugar. Add eggs, bananas, and vanilla. Continue beating while you sift flour, baking soda, and salt. Add dry ingredients to banana mixture. Add nuts. Bake at 350 for 60-70 minutes for a loaf, or about 20 min for muffins.