Preheat your oven to 350°F (180°C).
In a medium bowl, whisk together the flour, baking soda, and salt.
In a separate large bowl, mix together the melted butter, granulated sugar, and brown sugar until well combined.
Add the egg and vanilla extract to the butter mixture and stir until smooth.
Gradually add the dry ingredients to the wet ingredients and mix until just combined. Be careful not to overmix.
Stir in the chocolate chips.
Transfer the cookie dough to a cast iron skillet and spread it out evenly.
Bake for 20-25 minutes, or until the edges are golden brown and the center is set.
Allow the cookie to cool slightly before slicing and serving.
Enjoy your delicious chocolate chip skillet cookie!