Banana Bread-Nutella Brownies

Step 1
Preheat the oven to 375 degrees F (190 degrees C). Grease and flour a 9×13-inch baking pan.

Step 2
Beat sugar, sour cream, softened butter, and eggs together in a bowl until creamy. Add mashed bananas and vanilla extract and blend again. Add flour, baking soda, and salt and blend again until smooth and creamy. Fold in walnuts. Spread batter evenly into the prepared pan.

Step 3
Bake in the preheated oven until a toothpick inserted in the center comes out clean, 20 to 25 minutes.

Step 4
Remove brownies from the oven, leaving oven on. Add chocolate-hazelnut spread to the top without spreading.

Step 5
Return pan to the hot oven until chocolate-hazelnut spread is softened, 2 to 3 minutes. Remove from oven and spread chocolate-hazelnut spread over brownies.

Step 6
Cut cooled brownies into 20 squares.