Preheat oven to 350° F.
In a large mixing bowl, combine the melted butters and both sugars. Add the vanilla extract and eggs and mix until combined.
In a separate mixing bowl, whisk together the flour, salt, and baking soda.
Gradually add flour mixture to the wet ingredients and mix until just combined. Gently fold the chocolate chips in by hand.
Grease a 10" cast iron skillet with with butter or spray with non-stick cooking spray. Transfer the batter into the skillet and spread into an even layer.
Bake for about 25 minutes or until the top is golden brown. Don't overbake because you still want the middle to be nice and gooey. Remove from the oven, top with ice cream, grab some spoons, and dig right in!