Using a #20 size scoop (roughly 3 Tablespoons), scoop the cookie dough onto a sheet pan lined with parchment. It's okay if all of the dough balls are on one sheet pan, you will not be baking them all together.You can adjust the size of your dollop and cookie scoop to be a larger cookie or a smaller cookie. Just remember your baking time will need to adjust too.
Refrigerate the dough balls for at least 30 minutes. The dough will be easier to work with once it's cold and it will allow the flour to absorb the moisture in the batter, which prevents spreading!
Once your dough balls have chilled, and the Nutella balls are frozen, you'll want to stuff your cookies. Divide your dough ball into 2 pieces, place the Nutella ball onto the bottom piece, and sandwich the other half on top. Make sure to completely cover the Nutella, and have a little more of the dough on the bottom of the cookie.
Place all of the stuffed cookies back on the tray and refrigerate for another hour, or overnight. This will give the dough and Nutella time to come to the same temperature, resulting in a more even bake.
An hour before you're ready to bake, preheat your oven to 375°F and prepare a cookie sheet with parchment paper.
Place 6 cookies onto the pan and top with a few extra chocolate chips. (optional)
Bake at 375°F for 10-15 minutes. Check the progress of the cookie at 10 minutes, the center may appear to be underdone, but it should look baked, and not "wet". If it does appear wet and shiny over the Nutella ball, continue to bake for an extra 2 minutes at a time until it is finished baking.
Cool the cookies on the tray for 5-10 minutes before attempting to move them to a cooling rack. The molten center will make it weak and could possible crack the cookie when you try to move it. Also, let it cool a bit before biting into it so the lava center doesn't burn the skin in your mouth. Ouch!
Transfer to a cooling rack and store at room temperature for up to 1 week. Nutella is shelf-stable, but if you're stuffing your cookies with other ingreidnets be sure to check the expiration date.