Heat oven to 375F. Spray with non-stick spray or cover pan with tin foil, (non-stick if you have it, otherwise spray it with non-stick spray) 15x10-inch jelly roll pan.
In a large bowl, using mixer, beat together sugars, sour cream, butter, and eggs until creamy.
Add in bananas and vanilla extract and blend.
Add flour, baking soda, salt, and continue to beat for 1 minute.
Spread batter evenly into pan.
Bake 20 to 25 minutes or until golden brown.
While bars are baking, you can make the frosting.
Heat butter in a large saucepan over medium heat until boiling and let butter turn a delicate brown color, then remove from heat immediately.
Add powdered sugar, vanilla extract, caramel dip and milk.
Whisk together all the ingredients until smooth. Frosting should be thicker than glaze but thinner than frosting.
Using a spatula, spread the brown butter frosting over the banana bars while they are still warm. I added the frosting about 15 minutes after I took the banana bars out of the oven. It makes it easier to spread onto the cake. YUM!!!