Prep. Preheat oven to 350°F (177°C) and spray the bottom and sides of a 9x5x3 inch loaf pan with cooking spray or brush with melted butter.
Mix dry ingredients. Whisk all dry ingredients in a medium bowl and set aside.2 cups flour, 1 teaspoon baking powder, 1 teaspoon baking soda and ½ teaspoon salt
Mash bananas. Mash about 2 large ripe bananas, then measure out 1 ¼ cups for the recipe. Measuring is important for the right texture, since bananas can vary in size.
Mix wet ingredients. Into another larger bowl, add the mashed bananas, all remaining wet ingredients, and whisk until very smooth. Add the dry ingredients and whisk until just combined. 1 cup packed light brown sugar, 1 cup sour cream, ½ cup oil and 1 teaspoon vanilla.
Bake. Transfer batter into the prepared pan, smooth top, and sprinkle chopped walnuts on top, if desired. Bake for 45 to 55 minutes or until a tooth pick inserted in the middle comes clean. Place the pan on a wire rack and cool completely.👉 If during baking, the top of the bread looks like it is getting too brown, cover it loosely with aluminum foil and continue to bake until done.
Notes
Banana – use over ripe bananas (dark yellow skin with lots of brown spots).Vegetable oil – Use a flavorless oil like vegetable or corn oil.