Preheat the oven to 350°F (175°C) and line a baking sheet with parchment paper.
In a mixing bowl, cream together the softened butter, brown sugar, and granulated sugar until light and fluffy.
Beat in the egg and vanilla extract until well incorporated.
In another bowl, whisk together the rolled oats, all-purpose flour, baking soda, ground cinnamon, and salt.
Gradually add the dry mixture to the wet mixture, stirring until just combined.
If desired, fold in the chocolate chips.
Using a cookie scoop or tablespoon, drop rounded tablespoons of dough onto the prepared baking sheet, leaving space between each cookie.
Bake in the preheated oven for 10-12 minutes, or until the edges turn golden brown.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.