Step 1

Preheat oven to 350°. Line a 9x5 inch loaf pan with parchment paper and spray lightly with cooking spray.

Step 2

Cream together butter and sugar the bowl of a mixer or large mixing bowl if doing by hand.

Step 3

Add eggs, one at a time. Mix until combined, it will look curdled. Add vanilla. Mix until well combined.

Step 4

Add mashed bananas and milk.

Step 5

Sieve flour, baking soda, and salt over the bowl. Gently mix until flour can no longer be seen in the batter.

Step 6

Microwave Nutella for 15 to 20 seconds, or until it loosens. Add 1 cup of batter and mix to combine.

Step 7

Spoon both batters alternately into the prepared pan. Use a chopstick or knife and gently swirl the chocolate into the banana batter.

Step 8

Bake for 50 minutes to one hour. A toothpick will come out with some crumb. Let cool in pan for 15 minutes, then remove and let cool completely on a wire rack.