Using a hand or stand mixer, mix the peanut butter, sugar, egg and vanilla on low speed until well combined. (Do not over mix!)
Scoop about 1 1/2 tablespoons of dough about 2 inches apart onto the baking sheet.
Flatten the dough balls with a fork, making a cross pattern on the cookies.
Bake the cookies for 10-12 minutes until they are golden around the edges. Allow the cookies to rest on the counter for 2 minutes before transferring them to a cooling rack.