Preheat the oven to 350 degrees.
Grease muffin tin or use cupcake liners.
Melt butter and stir in sugar.
Combine mashed bananas, applesauce, eggs, and vanilla. Then stir in melted butter and sugar.
Combine the flour, salt, baking soda, and baking powder. Then add these dry ingredients to the banana mixture.
Next stir in the chocolate chips and walnuts if using.
Bake for 25 minutes or until a knife/ toothpick comes out clean. Enjoy!