Heat oven to 350 degrees. Line 2-3 baking sheets with parchment paper. Set aside.
In a medium-size bowl, whisk together oats, flour, salt, baking soda, and cinnamon.
To the bowl of a stand mixer, add the butter, peanut butter, white and brown sugars. Beat until creamy, about 2 minutes. Add the egg and vanilla and beat until blended.
Set the mixer to low and add in the dry ingredients. Mix until combined. Scrap down the sides of the bowl. Using a large cookie scoop, #16, scoop out cookie dough and place on prepared baking sheets, leaving about 2 inches between cookies. Place 6 cookies per baking sheet. Bake cookies in the oven for 12-15 minutes until golden brown on the edges but the center still soft. Be careful not to over bake.
Remove from the oven and let cool on the baking sheet for 5 minutes then place on a wire rack.
Serve or store in an airtight container at room temperature.