In a large mixing bowl, add brown sugar, 1/2 cup granulated sugar, softened butter and peanut butter. Using a hand mixer (or stand mixer if you have one), beat on MED speed until light and fluffy, about 1-2 minutes.
Add egg and vanilla and beat until well mixed. Add flour, baking soda, and salt, and beat on LOW until combined and no flour streaks remain. Scrape the bowl if needed.
Cover bowl with plastic wrap and refrigerate for 30 minutes or more. Add unwrapped chocolate kisses to a bowl and refrigerate as well, until ready to add to baked cookies.
When ready to bake, preheat oven to 375 F degrees. Line a baking sheet with a sheet of parchment paper and set aside. Add final 1/2 cup granulated sugar to a small shallow bowl, and set aside.
Using a small cookie scoop (1.5 tablespoon size is perfect), or your hands, shape dough into balls a little larger than 1 inch in diameter. Gently roll balls in bowl of granulated sugar to coat on all sides.
Place approximately 2 inches apart on prepared baking sheet and bake 9-10 minutes, until lightly golden brown and tops of cookies have a cracked appearance.
Press a chocolate kiss into the center of each cookie, then remove to a cooling rack to continue cooling.
