Combine the flour, baking soda, and 1 tbsp of the cinnamon in a medium size bowl and set aside. In another small dish, combine the remaining 1 tbsp of cinnamon and 1/4 cup of the white sugar and set that aside as well.

Cream together the butter, brown sugar, and remaining white sugar in the bowl of a stand mixer fitted with the paddle attachment. Add in the prepared egg and vanilla, and continue mixing until everything is combined.

With the mixer running on low, slowly add in the flour mixture, a little at a time and mix until everything comes together. Add in the oatmeal and continue mixing until the oatmeal is well-distributed throughout the dough.

Scoop out dough with a medium size cookie scoop and roll it into balls, placing the dough balls on a silpat-lined baking sheet. When the sheet is full, bake in a 350° oven for 15 minutes, rotating the baking sheet halfway through.

When the cookies are removed from the oven, gently squish them down into shape with the back of a spoon. Allow them to cool on the baking sheet for a few minutes, then transfer to a wire rack to cool completely.