Preheat oven to 375 degrees Fahrenheit (190 degrees Celsius).

Line two large baking sheets with parchment paper or silicone baking mats. Set aside.

Combine the flour, baking soda, baking powder, salt and cinnamon in a medium bowl, then set the dry ingredients aside.

In the bowl of a standing mixer fitted with the paddle attachment, or in a large bowl with a handheld mixer, beat the softened butter, granulated sugar and brown sugar on medium-high speed for 1 minute.

Add the egg and vanilla and beat on medium-high speed for 1 minute.

Then, add the dry ingredient mixture and beat to combine.

Add the oatmeal and beat on medium speed until incorporated.

Stir in the chocolate chips on low until evenly distributed throughout the dough.

Use a 2 Tablespoon cookie scoop to measure out portions of dough.

Roll the dough into balls and place evenly spaced on the prepared cookie sheets (8 or 9 per cookie sheet).

Gently press down the tops of the oatmeal cookies until they are slightly flattened (if you want thicker cookies, skip this step).

Bake in the preheated oven for 8-10 minutes until the top is just set and the edges are lightly browned.

Let sit on the baking pan for 5 minutes before transferring to a wire rack to cool.