Preheat oven to 350 degrees. Prepare a baking dish with parchment paper. Leaving overhang to make it easy to pull them out.
Cream together butter, brown sugar, and sugar in a stand mixer (or with a hand mixer and a large mixing bowl). Mix in eggs one at a time then vanilla extract.
In a separate bowl whisk together flour, baking powder, baking soda, salt, and oats. Add these to your wet ingredients.
Fold in chocolate chips then spread into your prepared baking dish. Bake for 30-35 minutes or until cooked through and golden brown. Use parchment paper over hand to remove from baking dish. Slice into squares and serve.