Step 1

1 Preheat the oven to 300 degrees

Step 2

2 Have a 10-inch cast-iron skillet at hand

Step 3

3 (This can be baked in a 12-inch skillet; check doneness after 25 minutes

Step 4

4 )

Step 5

5 Combine the butter and sugars in the bowl of a stand mixer or handheld electric mixer; beat on medium speed for about 5 minutes, until light and fluffy

Step 6

6 Add the vanilla extract

Step 7

7 Reduce the speed to medium-low; add the eggs one at a time, beating until fully incorporated

Step 8

8 Stop to scrape down the bowl

Step 9

9 Add the flour, baking soda and salt

Step 10

10 Beat on medium-low speed to form a firm dough, then add the chocolate chips and beat on low speed just until evenly distributed

Step 11

11 Press half the cookie dough into the bottom of the skillet

Step 12

12 Spread the Nutella evenly over that dough, leaving a 1/2 inch margin around the edge

Step 13

13 (This is easy to do with an offset spatula

Step 14

14 ) Top with the remaining cookie dough, making sure to cover the Nutella completely at the edges -- sealing them, if you can

Step 15

15 Bake (middle rack) for 25 to 35 minutes; or until the edges are golden brown, and the top looks slightly under-baked, yet it should be fairly firm to the touch

Step 16

16 Transfer to a wire rack to cool; the residual heat from the pan should continue to cook the cookie for a bit

Step 17

17 Let sit for at least 10 minutes before serving