Preheat oven to 300 degrees F. Line baking sheets with parchment paper.
Cream 1 cup softened butter with ¾ cup + 1 tablespoon granulated sugar, and ¾ cup packed light brown sugar in the bowl of a stand mixer on medium speed for about 2 minutes.
Add 2 large eggs, 1 & ¼ teaspoons vanilla, and ¼ teaspoon lemon juice, blending with mixer on low speed for 30 seconds, then medium speed for about 2 minutes, or until light and fluffy, scraping down the bowl.
With mixer on low speed, add 2 & ¼ cups flour, ½ cup rolled oats, 1 teaspoon baking soda, 1 teaspoon salt, and a pinch of cinnamon, blending for about 45 seconds. Don’t overmix.
Remove bowl from mixer and stir in 2 & ⅔ cups chocolate chips and 1 & ¾ cups chopped walnuts.
Portion dough with a scoop (about 3 tablespoons) onto lined baking sheets, 3 inches apart. (If the dough seems overly soft, refrigerate it for about 20 minutes before baking.)
Bake at 300F for 20-23 minutes, or until edges are golden brown and center is still soft.
Remove from oven and cool on the baking sheet for about 1 hour.
Serve with a cold glass of milk and enjoy!