Preheat oven to 350 Fahrenheit (or 180 Celsius)
Mash ripe bananas with a folk
Wet ingredients: In a large bowl, combine the mashed banana, melted butter, milk, yogurt, egg, and vanilla extract. Mix well.
Dry ingredients: In a large bowl, combine flour, baking soda, baking powder, salt, and ground cinnamon.
Pour the wet ingredients into the dry and stir until everything is just combined and you have a nice thick batter. Add chopped walnut and mix well.
Then fill muffin tins 3/4 full and top with chopped walnut.
Bake for 18 to 20 minutes or until set through and a toothpick comes out clean. Let cool on a wire rack.
Serve and enjoy!