Step 1

Preheat oven to 350 and grease a 9x13 pan.

Step 2

In large bowl, whisk together flour, baking soda, salt and cinnamon.

Step 3

In separate bowl, beat together softened butter, sugar, sour cream, vanilla and eggs until smooth.

Step 4

Beat in the mashed bananas until well combined.

Step 5

Gradually mix in the dry ingredients until well combined

Step 6

Fold in the 1/2 cup chopped walnuts.

Step 7

Pour batter into prepared pan.

Step 8

Bake 25-30 minutes or until golden brown and toothpick comes out clean.

Step 9

Once cooked through, allow to cool 15 minutes.

Step 10

To make frosting, melt butter over medium heat for 2-4 minutes. Watch the butter carefully, once it starts to turn a slight brown color and smell like roasted nuts, then its ready. Be careful not to burn the butter.

Step 11

Remove butter from heat and whisk in the powdered sugar, milk and vanilla. Add in 1-2 more tbsp milk to thin out the frosting.

Step 12

Spread frosting over brownies and top with chopped walnuts.

Step 13

Allow frosting to harden for an hour before cutting and enjoy!