Preheat the oven to 350 degrees and line two baking sheets with silicone baking mats or parchment paper.
In a medium-sized mixing bowl, whisk together the flour, baking soda, cinnamon, and salt. Set aside.
Using an electric stand mixer with the paddle attachment, cream together the butter, brown sugar, and sugar on medium-high speed until smooth and combined (about 1-2 minutes). Add the eggs, one at a time, mixing well after each one. Then add the vanilla extract. Be sure to scrape the bottom and sides of the bowl.
Slowly add the flour mixture and mix at low speed just until combined. Then gently mix in the oats. Remove the bowl from the stand and use a silicone spatula to fold together any remaining loose ingredients.
Use a cookie scoop (I used my 1.5 tbsp) to scoop out the dough and roll it into a ball in your hands. Place the cookie dough balls onto the prepared baking sheet, about 2-inches apart, and bake for 8-10 minutes (the edges should be lightly browned and the tops will look slightly underdone).
Let the cookies rest on the pan for 5-10 minutes as they'll finish baking and start to set (they may look underdone but they're not). Then transfer the cookies over to a wire baking rack to finish cooling completely.