In a medium mixing bowl, add and whisk together the flour, baking soda and salt. Set bowl aside.

In a separate large mixing bowl, add the butter, brown and granulated sugars. Using a spatula or hand held electric mixer, mix ingredients together to thoroughly combine.

Next, mix in the egg, egg yolk and vanilla extract. Add all of the flour mixture into the bowl with the wet batter and gently mix until a soft cookie dough forms. Mix in the chocolate chips into the cookie dough.

Spoon two-thirds of the chocolate chip cookie dough into the prepared baking pan. Use a spatula or hands to pat the cookie dough into an even layer while creating a border, about 1/4 to 1/2 inch high.

Spoon the Nutella into the cookie dough base. With the remaining cookie dough, pat into an even layer and place over the Nutella filling. Gently press along the edges of the bottom and top cookie dough layers to seal.

Sprinkle additional chocolate chips over the top of the cookie pie. I like to add a few chocolate wafers as well but this is optional.

Transfer cookie pie to the center rack in preheated oven and bake for 35 to 40 minutes or longer as needed. Cookie pie is ready when it is fully golden brown with crisp edges. The center of the pie should appear fully baked and not wet or doughy. If cookie pie starts to become overly brown before it is fully baked, tent the baking pan with a sheet of aluminum foil and continue to bake.

Remove cookie pie from the oven and cool at room temperature for about 45 to 60 minutes to set. Cut into equal slices and serve as is or with whipped cream or ice cream. Enjoy!