Banana Bread Bars with Brown Butter Frosting

• 1½ cups white sugar
• 1 cup sour cream
• ½ cup butter, softened
• 2 eggs
• 1¾ cups mashed ripe bananas
• 2 teaspoons vanilla extract
• 2 cups all-purpose flour
• 1 teaspoon baking soda
• ¾ teaspoon salt
• ½ cup chopped walnuts (optional)

Frosting:

• ½ cup butter
• 4 cups confectioners’ sugar
• 3 tablespoons milk
• 1½ teaspoons vanilla extract

Instructions:

1. Preheat oven to 350 degrees F (175 degrees C). Grease and flour a 15×10-inch jelly roll pan.
2. Beat white sugar, sour cream, ½ cup softened butter, and eggs in a bowl with an electric mixer until creamy. Beat in bananas and 2 teaspoons vanilla extract. Add flour, baking soda, and salt; mix for 1 minute. Stir walnuts into batter until evenly incorporated. Spread batter in prepared pan.
3. Bake in the preheated oven until golden, about 27 minutes. Cool.
4. Melt ½ cup butter in a large saucepan over medium heat until bubbling and golden brown, 3 to 5 minutes. Remove from heat.
5. Whisk confectioners’ sugar, milk, and vanilla extract into melted butter until a smooth frosting consistency is reached. Spread frosting over cooled banana bars.