In a large mixing bowl, or the bowl of a stand mixer, cream butter and sugars. Beat in egg and vanilla extract.
In a small mixing bowl, whisk together flour, baking soda, baking powder and salt. Add to butter mixture and stir until almost combined. Add chocolate chips and oat and stir until everything is fully combined.
Pour batter into an un-greased pie pan.
Bake for 20-25 minutes or until edge is golden and top is lightly browned. Allow the cookie pie to cool for at least 1 minutes before slicing. At first it will be soft but will harden as it cools down. Cut into 8 slices.