Preheat oven to 350 degrees. Grease and flour an 8 x 8 baking dish.

Melt butter and 1 1/2 cups of bittersweet chocolate chips in a pan over low heat. Once melted remove from heat and let cool, about 10-15 minutes. (If you don’t let it cool, your brownies will be cakey instead of chewy.)

In a bowl beat sugar, eggs and vanilla together. In another bowl mix flour and salt.

Once the chocolate has cooled, mix it into the egg mixture. Then slowly add flour mixture and mix until combined. Fold in remaining chocolate chips and nutella. Batter will be thick.

Spread brownie mix into baking dish. Bake for 35 - 45 minutes or until toothpick inserted comes out with a few crumbs on it. Allow to cool before cutting. Serve.