Preheat oven to 350°
In a large bowl, using a wooden spoon, combine melted butter and both sugars. Stir until there are no lumps.
Add in vanilla, egg and yolk. Stir until mixture is smooth and egg is fully incorporated.
Stir in flour, baking soda and salt until incorporated.
Fold in chocolate chips.
Spread evenly in a 10″ cast iron skillet.
Bake 15-20 minutes until edges start to golden. Don’t overcook. The center will appear slightly loose.
Let cool 10 minutes on wire rack and scoop onto plates or bowls.
Serve with vanilla ice cream.
