• Line two baking sheets with parchment paper and preheat the oven to 300°F.
• Add the sugars and butter to the bowl of a stand mixer. Mix, on medium speed, until creamy, about 2 minutes.
• Add eggs, vanilla and lemon juice to the bowl. Mix on low speed to incorporate, about 30 seconds. Then, turn the mixer to medium speed and continue to mix until fluffy and light, about 2 more minutes. Be sure to scrape down the sides of the bowl.
• Turn the mixer down to low speed and add the flour, oats, baking soda, salt, and cinnamon. Only mix until incorporated, about 45 seconds. Do not over mix.
• Take the bowl off of the mixing stand. Add the chocolate chips and walnuts and use a spoon or spatula to stir.
• Scoop the dough onto the parchment paper lined pans. Each dough ball should be about 3 tbsp. Also, be sure that the dough is placed about 2 inches apart on the sheet.
• Bake for 20-23 minutes. The edges will be golden brown and the center should still be soft.
• Remove from the oven and allow the cookies to completely cool while still on the baking pan, about 1 hour.

Note: You can freeze the dough balls. When you're ready to bake, place the frozen dough balls on the lined baking sheets and into the oven. You do not need to thaw them. Bake at 300°F for 23-25 minutes or until edges are golden and middle is soft.