Preheat the oven to 375°F. In a medium sized mixing bowl, combine the flour, baking powder, baking soda, and salt. Whisk to combine and set aside.
In a large mixing bowl or bowl of a stand mixer, beat the butter with a handmixer or stand mixer until it is creamy, about 1-2 minutes, scraping down the sides as needed. Add the granulated sugar and brown sugar, beating until smooth. Add the egg, peanut butter and vanilla. Beat on medium-high speed until the batter is smooth and no lumps remain. Add the dry ingredients to the batter and mix until just combined and no dry bits remain (don't overmix).
Using a cookie scoop, scoop the cookie dough (1 ½ - 2 tablespoon per cookie). Roll the cookie dough into a ball. In a shallow bowl, add the granulated sugar or sanding sugar and roll the cookie dough balls in the sugar until they are completely coated. Place the cookies on a baking sheet, leaving space in between each cookie. Bake for 8-10 minutes until the bottoms of the cookies are a light golden brown. Transfer the cookies to a cooling rack and let the cookies cool slighty.
While the cookies are still warm (but not hot) press a Hershey Kiss chocolate into the center of each cookie. Let the cookies cool completley before serving or storing.
Notes
To prevent the Hershey Kiss chocolate from melting, chill it in the refrigerator or freezer before adding it to the warm cookies.
Classic store-bought smooth peanut butter works best for these cookies. Natural peanut butter can still be used, but it will give them a crumbly texture.
Hershey's Kisses are the classic chocolate candy to use for these cookies, but any chocolate will work, like mini Reese's Peanut Butter Cups!
For a nut-free version, use Wowbutter or Sunbutter sunflower seed butter.
Use colored sanding sugar or make your own colored sugar to roll the cookie dough balls in for a fun, festive color. To make your own colored sugar, add a couple of drops of food coloring to granulated sugar and shake it together in a jar until the sugar is fully colored.
Unwrap the chocolates while the cookies are baking. The chocolates need to be added while the cookies are still warm, and unwrapping them one by one takes some time.