Begin by preheating the oven to 350° F (176° C). Have ready a cookie sheet which can be lined with a silicone baking mat if desired. No greasing is necessary.
In the bowl of a stand mixer or a large bowl, add all of the ingredients except the flour: the butter, the sugars, peanut butter, egg, vanilla, salt, and cinnamon. Beat these ingredients together until they are well combined and the color has lightened.
Turn the mixer to low and slowly add the flour. Stir together until everything has just mixed. Turn the mixer off to scrape the bowl and combine any remaining bits of flour with a spatula.
Drop about a tablespoon of batter onto the cookie sheet about 2” apart.
Bake for 12-15 minutes, rotating the sheet halfway through, until the edges are slightly golden brown. Avoid over-baking to ensure soft cookies.
Let the cookies cool on the baking sheet on top of a rack for 5 minutes then remove the cookies to the rack to cool completely.