Preheat the oven to 350°F and line two baking sheets with parchment.
Whisk together the flour, baking soda, and salt in a bowl.
Beat the butter and peanut butter together until smooth, about 2 minutes. Add the granulated and brown sugars and beat until fluffy.
Beat in the egg and vanilla until combined.
Add the dry ingredients and mix on low speed until just combined.
Roll the dough into 36 balls, about 1 tablespoon each, then roll each in granulated sugar.
Place 2 inches apart on the sheets and bake for 8–9 minutes, until the edges are just set.
Immediately press a chocolate kiss into the center of each cookie. Cool on the pan for 5 minutes before transferring to a wire rack.