Preheat oven to 350°F.
Line baking sheets with parchment paper.
Cream butter, peanut butter, granulated sugar, and brown sugar until smooth.
Add egg and vanilla extract.
Mix in flour, baking soda, and salt.
Roll dough into balls.
Roll each dough ball in granulated sugar.
Place on prepared baking sheets.
Bake for 8–10 minutes.
Remove from oven.
Immediately press a Hershey's Kiss into the center of each cookie.
Allow cookies to cool completely before serving.