Preheat oven to 350°F. In a large bowl, combine butter and sugar with a wooden spoon. Stir in egg and vanilla. Stir in flour, baking soda, and salt. Stir in chocolate chips. Transfer to a 10-inch cast-iron skillet; smooth top.
Bake until cookie is golden brown and just set in the center, 18 to 20 minutes. Let cool 5 minutes.
Serve with a scoop of vanilla ice cream.
Recipe by Life at Cloverhill at https://lifeatcloverhill.com/2013/11/chocolate-chip-skillet-cookie.html