In a large bowl, mix brown sugar, 1/2 cup granulated sugar, softened butter and peanut butter using a hand mixer. Beat on medium speed until light and fluffy, just for a couple of minutes.

Add in the egg and vanilla, beat until well mixed. Add flour, baking soda, and salt, and beat on low until fully combined.

Cover bowl with plastic wrap and refrigerate for 30 minutes.

Preheat oven to 375 F degrees. Line a baking sheet with a cookie mat or parchment paper and set aside.

Add the additional 1/2 cup granulated sugar to a small bowl, and set aside.

Shape 1 1/2 Tablespoons of cookie dough into a 1 inch ball using your hands. Gently roll balls in the 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 brown and tops of cookies look a bit cracked.

Press a Hershey chocolate kiss into the center of each cookie, then remove to a cooling rack to continue cooling.