Nutella Chocolate Chip Cookie Cake

Preheat oven to 350°F. Grease a 9-inch round baking dish. In a bowl, using a stand mixer fitted with a paddle attachment, beat the butter for 2 minutes on medium speed till smooth. Add brown sugar while beating on medium speed until combined, about 2 minutes. Mix in egg + yolk and vanilla on medium-high speed for about a minute. Scrape down the sides of the bowl. In a separate bowl, combine flour, cornstarch, baking soda, and salt. On low speed, slowly mix into the wet ingredients until combined, mixing in 1/4 cup at a time. Add 1 1/3 cup of chocolate chips and mix for 10 seconds till combined. Take half the cookie dough and press the dough evenly into the prepared pan. Scoop the Nutella with a spoon and spread it on top of the cookie dough. Take the other half of the cookie dough and press down evenly on top of the Nutella layer. Bake for 30 minutes or till the cake is lightly golden brown. Remove from the oven, to cool completely, about an hour. Once cooled, use a sharp knife to cut cake! Top off with ice-cream and whip-cream!