01 - Preheat oven to 350°F. Grease and flour a 9x5-inch loaf pan or line with parchment paper.
02 - In a large bowl, cream softened butter and sugar until light and fluffy using electric mixer or whisk.
03 - Beat in eggs one at a time. Mix in sour cream and vanilla extract until well combined.
04 - Stir mashed bananas into wet mixture until fully incorporated.
05 - In separate bowl, whisk together flour, baking soda, and salt.
06 - Gradually add dry ingredients to wet mixture. Mix gently until just combined—do not overmix.
07 - Fold in walnuts, pecans, or chocolate chips if using.
08 - Transfer batter to prepared loaf pan. Smooth top with rubber spatula.
09 - Bake 55-65 minutes until toothpick inserted in center comes out clean or with few moist crumbs.
10 - Cool in pan 10 minutes. Remove to wire rack and cool completely before slicing.