Step 1: Preheat your oven to 350°F (175°C).
Step 2: In a large mixing bowl, cream together softened butter, granulated sugar, and brown sugar until light and fluffy.
Step 3: Add eggs, vanilla extract, and lemon juice to the mixture; beat until fully incorporated.
Step 4: In another bowl, whisk together flour, oats, baking soda, salt, and cinnamon.
Step 5: Gradually mix the dry ingredients into the wet ingredients until just combined.
Step 6: Fold in chocolate chips and walnuts.
Step 7: Scoop rounded balls of dough onto a baking sheet lined with parchment paper, spacing them about 2 inches apart.
Step 8: Bake for 12-15 minutes or until edges are golden brown.
Step 9: Allow cookies to cool for 5 minutes on the baking sheet before transferring to a wire rack.
