01 - Preheat the oven to 350°F. Lightly grease a 10-inch ovenproof skillet, preferably cast iron.
02 - In a medium bowl, whisk together all-purpose flour, baking soda, and salt.
03 - In a large bowl, whisk melted butter, granulated sugar, and brown sugar until smooth and well combined.
04 - Add the egg and vanilla extract to the wet mixture and whisk until fully integrated.
05 - Gradually stir the dry ingredients into the wet ingredients until just combined.
06 - Fold in semisweet chocolate chips and nuts if using.
07 - Spread the dough evenly in the prepared skillet.
08 - Bake for 22 to 25 minutes until the top is golden, edges are set, and the center remains slightly soft.
09 - Allow to cool for 5 minutes before serving warm, optionally topped with ice cream.