Preheat the oven to 350°F (175°C).
In a large bowl, mix the peanut butter, granulated sugar, brown sugar, and egg until smooth.
Add the baking soda, salt, and flour to the mixture until combined.
Scoop tablespoon-sized balls of dough and roll them in sugar.
Place the dough balls on a lined baking sheet, spacing them about 2 inches apart.
Bake for about 10-12 minutes, or until the edges are set but the centers are still slightly soft.
Remove from the oven and immediately press a chocolate kiss into the center of each cookie.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring them to a wire rack.