1Heat oven to 350^.
Beat butter and sugars in a large mixer bowl, until fluffy.
Add egg and vanilla; beat well. Combine remaining dry ingredients in a small bowl; mix up and add to creamed mixture; mix up.
Stir in oats and chocolate chips mix up good.
Press dough evenly into a lightly sprayed 10-inch cast iron or non stick oven proof skillet.
Bake 20 miinutes or until top is lightly browned. (DO NOT OVER BAKE); cookie will continue to bake after it is removed from oven. Cool about 10 minutes.
Cut into 8 or 16 wedges.
Serve with ice cream, and topping of your choice.