Cream together butter, white and brown sugar in a bowl until smooth.
Add peanut butter, egg, and vanilla. Mix well and scrape down sides of the bowl.
Add flour, baking soda, and salt, mixing just until incorporated (be careful not to over-mix).
Scoop dough into balls using an ice cream scoop (or a spoon) and place on a greased cookie sheet. Press down slightly with fingers. Bake at 350 F for 8 minutes, or until the cookies are just set. Remove from oven and place a Hershey Kiss into the center of each cookie.
Return to oven for 2 minutes. Remove from oven and let cookies sit for 5 minutes before removing to cooling rack.