STEP 1: Combine all ingredients except peanut butter. In a medium-sized bowl, add the brown sugar, granulated sugar, baking soda, salt, egg, and vanilla.
STEP 2: Whisk vigorously. Whisk the ingredients vigorously until fully combined and smooth.
STEP 3: Fold in the peanut butter. Fold in the peanut butter with a rubber spatula, mixing for about 2-3 minutes to until fully incorporated.
STEP 4: Portion the cookie dough. Using a 2 tablespoon cookie scoop, portion the cookie dough onto one baking sheet lined with parchment paper. Freeze cookie dough for 15 minutes.
STEP 5: Roll cookie dough in sugar. Roll the frozen cookie dough in granulated sugar and place on the prepared baking sheet spaced about 2 inches apart.
STEP 6: Bake. Bake the cookies for 8 minutes or until barely golden on the edges. Immediately use a medium round cookie cutter or glass to scoot the edges of each cookie, making them perfectly round. Allow to cool for 2 minutes, then press a frozen kiss into each cookie. Allow to cool completely on the baking sheet.