Ingredients:

1/2 cup unsalted butter, softened
1 cup granulated sugar
2 large eggs
1 cup sour cream
1 teaspoon vanilla extract
2 ripe bananas, mashed
2 cups all-purpose flour
1 teaspoon baking soda
1/4 teaspoon salt
For the Frosting:

1/2 cup unsalted butter
2 cups powdered sugar
1 teaspoon vanilla extract
3 tablespoons milk
1/4 cup chopped walnuts (optional)

Directions:

Prepare the Batter:
Preheat your oven to 350°F (175°C). Grease and flour a 9×13 inch baking dish. In a large bowl, cream together the softened butter and granulated sugar until light and fluffy. Beat in the eggs, one at a time, then stir in the sour cream and vanilla extract. Mix in the mashed bananas until well blended. Combine the flour, baking soda, and salt; stir into the banana mixture.
Bake:
Spread the batter evenly into the prepared baking dish. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out clean. Allow the brownies to cool in the pan.
Make the Frosting:
In a medium saucepan, melt the butter over medium heat. Cook until the butter turns a golden brown, about 3-4 minutes. Remove from heat and whisk in the powdered sugar, vanilla extract, and milk until smooth. If the frosting is too thick, add a little more milk.
Finish and Serve:
Spread the frosting over the cooled brownies. Sprinkle with chopped walnuts if desired. Cut into squares and serve.

Prep Time: 20 minutes | Cooking Time: 30 minutes | Total Time: 50 minutes | Servings: 12 servings | Kcal: 350 kcal per serving