If you want to use homemade Nutella and you haven’t made it yet, go ahead and prep it now. Here’s how to make homemade Nutella. If you don’t want to use homemade, skip this step and use your favorite store-bought Nutella or chocolate hazelnut spread. Preheat oven to 350°F and line an 8x8 pan with parchment paper, leaving a 1” overhang for easy removal.
In a large bowl, vigorously whisk the eggs and sugar together for 1 minute, which helps to create the crackly top on top of the brownies.
To that same bowl, whisk in ⅔ cup of the Nutella, along with the butter and vanilla.
In a separate bowl, stir the flour, cocoa powder and salt together.
Pour the dry ingredients into the wet, then gently fold together with a rubber spatula until the flour disappears. Transfer the batter to the prepared baking pan.
Use a spoon to dollop the remaining Nutella over the batter, then use a knife to gently swirl it.
Place the pan in the oven and bake the brownies for 33-36 minutes, or until a toothpick comes out clean. Allow the brownies to cool completely in the pan, then pull on the parchment paper to remove them.
Slice into 9 large brownies or 16 smaller brownies and enjoy!