Preheat oven to 350.
Cream melted butter, sugars, and vanilla together until smooth
Add in egg and egg yolk and mix well.
In a separate bowl mix flour, baking powder, and salt. Add into wet ingredients.
Add in your chocolate.
Spray a 10 inch skillet and press dough into it. Bake 15-20 minutes. Dont over bake. Lean on the side of under cooked because it continues to cookie in the skillet after its done.
Wait until cooled, serve with ice cream.