Brown Butter Frosting:
1/2 c. butter
4 c. powdered sugar
1-1/2 tsp. vanilla extract
3 tbsp. milk
Bars:
Heat oven to 375F.
Grease and flour 15×10-inch jelly roll pan.
In a large bowl, beat together sugar, sour cream, butter, and eggs until creamy. Blend in bananas and vanilla extract. Add flour, baking soda, salt, and blend for 1 minute. Stir in walnuts.
Spread batter evenly into pan. Bake 20 to 25 minutes or until golden brown.
