Preheat oven to 375° F.
Place cast iron skillet in oven to preheat.
In a medium bowl, combine flour, baking soda and salt, sift ingredients together by stirring with a whisk.
In the bowl of your stand mixer, add butter, organic sugar and coconut sugar, cream together.
Add eggs, one at a time, beating well after each to incorporate.
Add vanilla and mix.
Slowly add flour mixture until incorporated.
Using a wooden spoon or spatula, stir in chocolate chips.
Carefully remove cast iron pan from oven. Spread cookie dough into pan evenly, pressing down with a spatula.
How much cookie dough you add will depend on the size of your pan. We like to make 2 small six inch skillet cookies and save some cookie dough for another night. (But we've also been known to toss the whole batch into our giant 15 inch skillet for a large crowd!)
Bake for 20 to 25 minutes or until golden brown. (Totally acceptable if the dough isn't completely set in the center! This is our favorite way!)
Cool in pan on wire rack for about 5 minutes, top with ice cream, pass around the spoons and dig in!
If family style isn't your thing, just slice it up like a pie!