Instructions
Place oats in a small food processor or blender and grind until they turn powdery. Place them in a medium sized bowl and whisk in the flour, baking soda, salt, and cinnamon. Set dry ingredients aside.
Stir together melted butter, brown sugar, and granulated sugar until smooth. You can stir by hand or use the bowl of a stand mixer. Stir in vanilla, lemon juice, and eggs. Mix on low speed until smooth, then stir in flour mixture. Mixture may be slightly lumpy because of the ground oats. Stir in chocolate chips and walnuts.
Line a cookie sheet with wax or parchment paper or a silicone baking mat. Portion dough into ¼ cupfuls place on the cookie sheet. You do not need to space them; this is just for chilling. Cover well with plastic wrap and chill at least 4 hours or overnight before baking.
Preheat oven to 350°F. Place cookies well spaced on cookie sheets lined with parchment paper or silicone baking mats. Slightly depress each ball with the palm of your hand.
Bake for 13-17 minutes. Do not over bake – these are best a bit under done. They're done when the edges are light golden brown and the center is no longer glossy.
Recipe Notes
You can chill the cookie dough balls for up to 3 days before baking or freeze them for up to a month.
Freeze baked cookies in an airtight container for up to 3 months. Thaw frozen cookies at room temperature.