This Nutella stuffed chocolate chip cookie cake is baked in a skillet so you can dig in with some spoons and ice cream or cut it into gooey slices of plated cookie cake. However you serve it, this epic cookie cake is bound to satisfy any Nutella lover's sweet tooth!
Preheat the oven to 350ºF (171ºC). Spray a 9" cast iron skillet with non-stick spray1. Set aside.
In a large bowl, toss together the flour, cornstarch, baking soda, and salt. Set aside.
In a medium size bowl, whisk together the butter, brown sugar, and granulated sugar until smooth. Whisk in the egg, egg yolk, and vanilla extract until completely combined.
Pour the wet ingredients into the dry ingredients and stir until no flour clumps remain. Fold in the chocolate chips.
Press a little less than half of the cookie dough evenly into the prepared skillet. Pour the melted Nutella into the cookie dough, then spread it into an even layer, leaving about ½" border around the edge.
Using your hands, break the remaining cookie dough2 into 4 chunks. Flatten each chunk slightly with your fingers and gently place on top of the Nutella. Seal any cracks where Nutella is peeking out.
When the top layer of cookie dough is all filled in, bake the cookie cake for 25-28 minutes until edges begin to brown. Remove from oven and allow to cool on a wire rack. I suggest allowing it to cool for at least 2 hours before cutting into slices, but if you want to put some ice cream on top and dig in with spoons, it only needs about 45-60 minutes to cool. Store leftovers covered tightly at room temperature up to 5 days. Cookie cake freezes well, up to 3 months. Thaw at room temperature, then warm in a 200ºF (93ºC) for 10 to 15 minutes before serving (or serve at room temperature).
Notes
Cast iron skillet: alternatively, you may use a 9" pie plate, springform pan, or round or square baking pan.
Handling dough: if dough is too soft, allow to sit at room temperature for a few minutes to cool down, or pop into the refrigerator for no more than 5 minutes.
All nutritional values are approximate and provided to the reader as a courtesy. Changing ingredients and/or quantities will alter the estimated nutritional calculations.