Preheat the Oven: Set your oven to 375°F (190°C). Grease a 13 x 9 inch baking pan thoroughly to ensure the brownies don’t stick.
Mix the Wet Ingredients: In a large bowl, beat together the sugar, sour cream, softened butter, and eggs until the mixture is smooth and creamy. This step is key for a soft and moist texture!
Add the Bananas and Vanilla: Fold in the mashed bananas and vanilla extract. These two ingredients add that unmistakable banana bread flavor we all know and love.
Incorporate the Dry Ingredients: Gradually mix in the flour, baking soda, and salt. Blend for about a minute to ensure all the ingredients are evenly combined.
Add the Walnuts: Stir in the chopped walnuts, which add a delightful crunch to each bite. If you’re not a fan of nuts, feel free to skip this step.
Bake: Spread the batter evenly in your prepared pan. Bake for approximately 25 minutes or until the top turns golden brown and a toothpick inserted into the center comes out clean.
Prepare the Frosting: While the brownies are cooling, heat the butter in a large saucepan over medium heat until it reaches a medium brown color. Carefully watch it to avoid burning.
Finish the Frosting: Remove from heat and gradually whisk in the powdered sugar, adding the milk little by little until the frosting reaches a smooth, spreadable consistency. Stir in the vanilla extract for an extra hint of sweetness.
Frost and Cool: Pour the frosting over the warm (but not hot) brownies and spread evenly. Allow the banana bread brownies to cool completely before cutting into squares.
Notes
Ripe Bananas: For the best banana flavor, use overripe bananas with brown spots. They’ll add natural sweetness and moisture.
Avoid Overmixing: When combining the wet and dry ingredients, mix just until everything is incorporated. Overmixing can make the brownies dense.
Browned Butter Frosting: This step adds a nutty, caramel-like flavor to the frosting. Make sure you don’t over-brown the butter, or it may taste burnt.
Nuts or No Nuts: If you have a nut allergy or prefer a smooth brownie, you can leave out the walnuts without affecting the texture too much.
