Banana Bread Bar with Brown Butter Icing

I pinned these several months ago.  Last Sunday I decided to make them because I had some bananas on hand that were turning.  I was worried, because sometimes pins look good, but really aren't that great.  But, these were very good.  They were very moist and very rich.  The icing was almost over the top, I think I would make it more of a glaze next time.  Anyways, I hope you enjoy this as much as I did.

• 1 and 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:

• 1/2 c. butter
• 4 c. powdered sugar
• 1-1/2 tsp. vanilla extract
• 3 tbsp. milk

Heat oven to 375F.  Grease and flour 15x10-inch jelly roll pan.  For the bars, 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.  Meanwhile, for frosting, heat butter in a large saucepan over medium heat until boiling.  Let the butter turn a delicate brown and remove from heat immediately. Add powdered sugar, vanilla extract and milk.  Whisk together until smooth (it should be thicker than a glaze but thinner than frosting).  Using a spatula, spread the brown butter frosting over the warm bars (the frosting will be easier to spread while the bars are still warm).