Banana Bread Brownies Recipe

1-1/2 c. sugar
1 c. sour cream
1/2 c. butter, softened
2 eggs
1-3/4 (3 or 4) ripe bananas, mashed
2 tsp. vanilla extract
2 c. all purpose flour
1 tsp. baking soda
3/4 tsp. salt
1/2 c. chopped walnuts (optional)

Brown Butter Frosting Recipe:
1/2 c. butter
4 c. powdered sugar
1-1/2 tsp. vanilla extract
3 tbsp. milk