Preheat the oven to 350 and ready to cookie sheets with parchment paper.
Whisk the whole wheat flour, rolled oats, baking soda and salt together in a large bowl.
In the bowl of your stand mixer fitted with the paddle attachment, cream the butter and sugars. Scrape down the sides and add the vanilla, egg, and egg yolk. Mix to combine. Scrape down the sides again and add the flour mixture in 3 small batches to combine. Fold in the chocolate chips.
Spoon out hefty tablespoon sized portions of the dough about 2 inches apart on the prepared baking sheets. Bake for 10 to 12 minutes. Cool on pans for 5 minutes before transferring to a wire rack to cool completely.