Super gooey gluten-free skillet cookie - aka pizookie! A thick chocolate chip cookie baked in a cast-iron skillet until the edge is golden brown and crisp and the center is oh-so gooey. Serve it straight from the warm skillet with scoops of vanilla ice cream and a handful of spoons, scooped into individual bowls, or cooled slightly and sliced into pie wedges.
In a medium bowl, sift together almond flour, tapioca flour, oat flour, baking soda, and salt. Set aside.
Place the sugars in the bowl of a stand mixer fitted with the paddle attachment or a large mixing bowl with a hand mixer or whisk and wooden spoon.
Brown the butter in a 10-inch cast-iron skillet (see note for pan and butter substitutions). Melt the butter over medium heat. First the butter will foams and then quickly brown. Take care not to burn the butter. Quickly pour the butter over the sugars in the mixing bowl. Mix and let sit for about 2 minutes to cool.
Add the egg and vanilla and mix very well, 2-3 minutes.
Reduce speed to low and gradually mix in the sifted flours, mixing until just combined. Then mix in 3½ ounces (~½ cup) of the chopped chocolate and, if using, ¼ cup of the peanuts, until evenly dispersed, reserving the remaining chocolate + peanuts (if using) on top.
Press cookie dough evenly into the skillet. (see notes for a peanut butter option.)
Top with reserved chopped chocolate and peanuts (if using) and bake for 20-22 minutes, until the edges are golden brown and firm to the touch and the center is just baked but very soft and gooey. When in doubt, err on the side of underbaked for the ultimate gooey cookie center.
Serve warm straight from the warm skillet (or warm in individual bowls) with scoops of vanilla ice cream and or chopped nuts.
Notes
Adding peanut butter to dough: If adding peanut butter, press ½ of the cookie dough into the bottom of the skillet. Then add dollop spoonfuls of peanut butter, equally 2 tablespoons. Scoop spoonfuls of the remaining cookie dough over top of the peanut butter, pressing until smooth. It's okay if some of the peanut butter peeks through!
Dairy-Free
Sub in plant butter or refined coconut oil 1 to 1 for the butter, melting it in the skillet, but not browning it.
Cast-Iron Skillet Substitution
Use any oven-proof 9 or 10-inch skillet or cake pan or an 8x8 baking pan. If using a baking pan, brown the butter in a saucepan and brush a small amount on the pan before pouring the browned butter over the sugar.This skillet cookie is not fussy, though. If you don't have any of these pans, you can use anything in the 8 to 11-inch range and adjust the baking time accordingly. For a smaller pan, you'll need to add a couple of minutes to the bake-time, and for a larger pan, start checking for doneness around 16 minutes.
Storing and Reheating
Slice and store any leftover skillet cookie in an airtight container at room temperature for up to 3 days. Store any portion that got ice cream on it in the fridge. Reheat in a 300°F oven for 5-7 minutes.