There is no better use for stale bananas than banana bread.
3 bananas (as ripe as possible)
6 tablespoons vegetable oil
1/2 cup sugar
1 teaspoon vanilla extract
1/4 teaspoon salt
1 1/2 cups all-purpose flour
1 teaspoon baking soda
1 teaspoon baking powder
Combine bananas, oil and sugar. Then add the egg, vanilla and salt.
Mix flour, baking soda and baking powder together in a separate bowl and add to banana mixture.
Pour into a greased loaf pan and bake at 350F for 45 minutes. Cool for 5 minutes in the pan, then turn out onto a wire rack and cool completely.