Preheat your oven to 350 degrees. You will need a 10 inch cast iron skillet or an oven safe skillet
Whisk the flour, baking soda and salt together in a medium size bowl. Set aside.
In the bowl of a stand mixer beat the butter and both sugars until light and fluffy. Add the vanilla and egg to the bowl, mix until well incorporated. With the mixer on low, add the flour mixture, mix until just incorporated. Stir in the milk chocolate chips.
Scoop the dough into a 10 inch cast iron pan or oven safe skillet. Press the dough to cover the bottom of the pan. Bake until edges are brown and the top is golden 40 - 45 minutes. Don't over bake the cookie, it will continue to bake in the pan after it's removed from the oven. Transfer to a wire rack, cool for 20 minutes. Cut into 8 wedges and serve with ice cream if desired.