Preheat your oven to 350°F (180°C). Line baking sheets with parchment paper.
In a bowl, whisk together oats, flour, baking soda, cinnamon, and salt. Set aside.
In another bowl, cream together softened butter, brown sugar, and granulated sugar until light and fluffy.
Add the egg and vanilla extract to the butter mixture, beating until well combined.
Gradually incorporate the dry ingredients into the wet mi
Fold in raisins or chocolate chips if desired.
Using a cookie scoop or spoon, drop rounded dough onto the prepared baking sheets.
Bake for 10-12 minutes or until the edges turn golden brown.
Allow cookies to cool on the baking sheets for a few minutes before transferring them to a wire rack to cool completely.