In a medium bowl, whisk together flour, salt, baking soda, and baking powder. Set aside.
Using a stand mixer with the paddle attachment, begin creaming the butter, granulated sugar and brown sugar until light and fluffy (2 - 3 minutes on medium speed). Scrape the bowl as needed. (note: a hand mixer may also be used)
Add the egg to the mixing bowl. Mix on medium speed until combined, scraping the bowl as needed.
Add the flour mixture and mix on low speed until combined.
Stir in the chocolate chips by hand.
Assemble and bake skillet cookies
Lightly brush each cast iron skillet with melted butter
Divide cookie dough evenly between the 6 skillets (approximately a scant ¼ cup of dough).
Using your hands or a dough tamper, lightly press dough evenly in each skillet.
Place skillets on a baking sheet. Bake in preheated oven for 12 - 14 minutes, or until tops and edges of cookies are browning.
Cool skillet cookies for 20 minutes before serving.
Enjoy!
Notes
Wrap any leftover skillet cookies in plastic wrap and store at room temperature for up to 2 days. If desired, reheat in a 300° F oven for 5 minutes to serve warm.
If desired, serve with a scoop of ice cream or drizzle with caramel or chocolate sauce.