Preheat your oven to 350F. Lightly spray a 6.5 inch cast iron skillet with a flour-based baking spray. Set to the side.
In a small saucepan, melt your butter over medium heat. Continue to heat until the butter turns a light brown color and has a nutty, caramel flavor.
In a medium-size mixing bowl, whisk together the light brown sugar, and granulated sugar
Add in the brown butter, egg yolk, and vanilla extract. Mix together until fully incorporated.
Stir in the flour until just combined and you no longer see any flour left in the cookie dough. Fold in the chocolate chips. (If your dough is too dry add 1 tbsp of milk at a time)
Press the cookie in a prepared skillet and top with more chocolate chips. Bake for 20 -22 minutes.
