Cooking (or baking) spray
1/2 teaspoon ground cinnamon
2 cups all-purpose flour
1 teaspoon baking soda
1/4 teaspoon salt
1 cup unsalted butter, divided, softened
1 cup granulated sugar
1 cup sour cream
2 teaspoons vanilla extract, divided
2–3 medium bananas, mashed (1-cup)
8 oz cream cheese, softened
1 cup powdered sugar
Milk, as needed
Salted Caramel Sauce
1 cup light brown sugar
4 tablespoons cold unsalted butter, divided
1/2 teaspoon kosher salt
2/3 cup heavy cream
1 cup chopped walnuts
Kosher or flaked sea salt for garnish
Preheat oven to 350ºF. Grease jelly roll pan with cooking or baking spray. Sift together cinnamon, flour, baking soda, and salt in small bowl. Set aside.
In bowl of a stand mixer cream together 1/2 cup butter and sugar until light and fluffy. Add eggs, one at a time, then sour cream ,vanilla, and bananas; mix until fully incorporated. Stop mixer and add half of dry ingredients. Turn machine on low speed and allow batter to come together, and then slowly add in remaining dry ingredients. Mix on low speed just until all ingredients are combined. DO NOT OVERMIX.
Pour batter into pan. Bake for 25–30 minutes or until wooden skewer/toothpick comes out clean when inserted into center. Allow to cool then turn bars out onto cooling rack.
In small bowl, or stand mixer, beat together remaining 1/2 cup butter and cream cheese until smooth. Stir in powdered sugar, and vanilla; add 1 tablespoon of milk at a time, and continue stirring on low until reach desired consistency. Spread frosting over cooled bars.
Salted Caramel Sauce
Place brown sugar in small saucepan. Add just enough water to cover surface of sugar. Add 2 tablespoons butter and turn heat to medium high. Allow mixture to melt—do not stir. When sugar is melted and bubbling carefully whisk in salt, cream, and remaining 2 tablespoons cold butter. Sauce will bubble violently, this is normal. Whisk mixture until smooth. Stir in walnuts and garnish with another pinch of salt. Slice frosted banana bars and drizzle with salted walnut caramel sauce.