Preheat the oven to 350ºF. Line a baking sheet with parchment paper or a silpat liner.

Place the oats in a blender or a food processor and pulse until they form fine crumbs.  Add the flour, baking soda, salt and cinnamon and pulse a few times to combine.

In a the bowl of a stand mixer or in a large bowl, cream together the butter, brown sugar, and granulated sugar.

Once combined, add the vanilla a lemon juice and mix to combine. Add the eggs, scraping the bowl as needed.

Add the flour mixture to the bowl and mix just until combined. Add in both chocolate chips and the walnuts and mix just to combine.

Divide the mixture into 24 equal portions and roll into balls. Place on the baking sheet at least 2 inches apart. (I usually do 8 cookies per cookie sheet.)

Bake in the preheated oven until light brown, 12-14 minutes. They may still look a tiny bit wet in the center - you don’t want to over-bake the cookies because they will continue to bake as they sit on the baking sheet.

Let the cookies sit on the baking sheet for 5 minutes before transferring to a wire rack or a sheet of wax paper to cool.