01 -
Heat the oven to 325°F. Line a 9-inch square baking dish with parchment paper, leaving extra hanging over all sides. Lightly coat the pan in nonstick spray.
02 -
Use a medium saucepan on low heat to melt together butter, chopped chocolate, and 1 cup of the chocolate chips. Stir continuously until smooth and let it cool down.
03 -
In a big bowl, whisk eggs, vanilla, sugar, and Nutella until smooth. Pour this into the cooled chocolate mix and combine.
04 -
Mix together the flour, baking powder, and salt by sifting them first. Then fold this into the chocolate batter. Gently stir in the last part of the chocolate chips and 1 cup of the chopped hazelnuts.
05 -
Spread the batter evenly into the pan, then top with remaining hazelnuts. Bake for 40 minutes. Tent foil over the pan and bake another 10-15 minutes until mostly set. Wait to cut until fully cool.