1. 4 ripe bananas (mashed) 2. 1/2 cup unsalted butter (melted) 3. 3/4 cup brown sugar 4. 2 large eggs 5. 1 tsp vanilla extract 6. 1 1/2 cups all-purpose flour 7. 1 tsp baking soda 8. 1/2 tsp salt 9. Optional: 1/2 cup chopped walnuts or chocolate chips