These banana bread brownies with brown butter frosting are nothing short of sinful! Made with ripe bananas and crunchy walnuts they're fluffy and moist with a rich frosting on top that makes them next level delicious!
Heat oven to 375°F. Line a 9x13" pan with parchment paper, or grease and flour. Set aside.
In a large bowl, beat together sugar, sour cream, butter, and eggs until creamy. Blend in bananas and vanilla extract.
In separate bowl, whisk (or sift) the flour, baking soda and salt together.
Add the flour to the banana mixture and mix just until combined. Stir in walnuts if desired. Spread batter evenly into pan and bake for 20 to 25 minutes or until a toothpick comes clean.
Prepare the frosting as the brownies bake by heating butter in a large saucepan over medium heat. Add the brown sugar to the melted butter and bring to a boil, stirring continuously for about 2 minutes. Remove from heat immediately.
Add powdered sugar, vanilla extract and milk. Whisk together until smooth (it will be thinner than frosting). Using a spatula, spread the brown butter frosting over brownies. This is best done when both ingredients are warm. Sprinkle chopped walnuts on top if desired.
Slice brownies into 24 squares. Serve warm, room temperature or even cold!
Notes
Variations:
Add chocolate chips to the batter before baking. Start with 1/2-1 cup.
Use Greek yogurt in place of sour cream.
Storage: Allow brownies to cool and store in a covered container for 3 days.Freezer Instructions: Place brownies on a baking sheet and freeze for 1 hour, or until hardened. Then place in a freezer container (you can stack with a piece of parchment paper in between each layer). Remove an hour before serving.