Preheat oven to 325 degrees F. Spray 13x9 inch baking dish with nonstick spray. Line pan with parchment paper if desired, then spray paper with nonstick spray.
In a large bowl mix together softened 1/2 cup + 2 tablespoons butter and brown sugar until well combined. Stir in flour, 1/4 cup cocoa powder, and 1/8 teaspoon salt until just combined. Press dough down into bottom of pan. Bake crust about 10-12 minutes or until slightly browned around edges.
Meanwhile, mix together granulated sugar, corn syrup, melted 2 tablespoons butter, vanilla, eggs, 2 tablespoons cocoa powder, and 1/8 teaspoon salt until well combined. Stir in chocolate chips and hazelnuts. Place cookies back in oven for another 25-30 minutes or until slightly browned and crackly on top. Cool completely.
SNAPPY TIPS: Be careful not to overcook the crust. It should not be completely cooked before adding the filling. I made my cookie bars in a dark pan. If you use a glass or light colored pan you may want to try a higher temperature such as 350 degrees F.SNAPPY SUBSTITUTIONS: Instead of unsweetened dark cocoa powder, you can use regular unsweetened cocoa powder. Instead of dark chocolate chips, you can substitute your favorite chocolate such as semi-sweet or bittersweet. Instead of hazelnuts, substitute your favorite nuts such as pecans, walnuts, or peanuts.
Keywords: chocolate hazelnut cookies, Christmas cookie, homemade pie bars