01 -
Heat oven to 325°F. Line a square 9-inch baking pan with parchment, letting extra hang over the edges, and coat with cooking spray.
02 -
On low heat, stir butter, chopped chocolate, and a cup of chocolate chips in a medium pot until smooth. Let cool down a bit.
03 -
In a big bowl, beat together the eggs, sugar, Nutella, and vanilla till blended. Mix this into the cooled chocolate combo.
04 -
Sift flour, salt, and baking powder together, then add this to the chocolate mix. Stir in the extra chocolate chips and 1 cup of the hazelnuts.
05 -
Spread the mix evenly into the prepped pan. Sprinkle the rest of the hazelnuts on top. Bake for 40 minutes. Cover with foil, then bake another 10-15 minutes until mostly firm. Let cool fully before slicing.