Preheat oven to 350 degrees. Spray 8×4-inch loaf pan with nonstick spray.

In a medium bowl, whisk together flour, baking soda & salt.

In a separate large bowl, beat sugar and butter with an electric mixer at medium speed until blended. Add eggs, one at a time, beating well after each addition. Add banana, milk and vanilla. Beat until blended.

Then add the dry ingredients to the wet ingredients and blend well to make the banana bread batter.

Spoon Nutella into a small dish and soften in the microwave for about 15 seconds. Add 1 cup of the banana bread batter to the Nutella and stir until blended well. Spoon Nutella batter alternately with plain banana bread batter into the prepared pan. Swirl batters together with a knife.

Bake 50 to 60 minutes, it will seem a tiny bit undercooked but that's what makes it good. Cool for at least 15 minutes in the pan, and then turn out onto a wire rack to cool completely.