Cream butter, brown, and granulated sugar with a mixer on medium speed for approximately 2 minutes.

Add in the eggs, vanilla, and lemon juice, blending for another 30 seconds at low speed and an additional 2 minutes on medium. The mix should become light and fluffy.

Place the mixer back on low speed and add in the flour, oats, salt, baking soda, and cinnamon. Don't overmix but blend for around 45 seconds until combined.

Remove the bowl from your mixer and stir in the chocolate chips and walnuts.

Using a cookie scoop, scoop out evenly spaced balls of dough (about 2 inches) on a parchment-lined cookie sheet.

Bake in a 300-degree oven for 20 - 23 mins or until golden brown, the center will still be soft.

Let cool on a baking sheet for about 1 hour or so.