Preheat your oven to 350°F. Line an 8x8 baking dish with parchment paper, spray with cooking spray and set aside.

In the bowl of your stand mixer fitted with the paddle attachment, beat the butter and brown sugar together for 2 minutes on medium speed. With the mixer still on medium add in eggs and vanilla and continue mixing until it’s smooth, scraping the sides of the bowl as necessary.

Turn the mixer down to medium-low and add in the Nutella and salt, mixing until it’s smooth and fluffy. Turn the mixer to low and add in the flour, mixing until just combined.

Spread the batter into the prepared pan evenly. Drop the remaining Nutella by the teaspoon-full evenly on top of the batter, and then using a butter knife swirl the Nutella into the batter.

Bake the brownies for 30-35 minutes until the center is just set.

Place the pan onto a wire rack and allow them to cool completely in the pan. When ready to slice, remove the foil from the pan onto a cutting board and cut into squares.