Instructions:
- Whisk together flour, baking soda, and salt in a medium bowl. Set aside.
- In the large bowl of an electric mixer, beat the softened butter, peanut butter, granulated sugar, and brown sugar until the mixture is light and fluffy (about 2-3 minutes). Scrape down the sides.
- Beat in the egg and vanilla extract until just combined. Be careful not to overmix the dough.
- Gradually add the dry ingredients to the wet mixture, mixing on low speed until just combined and a soft dough forms.
- Cover the dough and refrigerate for a minimum of 30 minutes. This chilling step is crucial to prevent spreading.
- Preheat oven to 375°F (190°C). Line baking sheets with parchment paper. Place the coating sugar in a shallow dish.
- Roll the chilled dough into uniform balls (about 1 tablespoon each). Roll each ball thoroughly in the coating sugar until completely covered.
- Place dough balls onto prepared sheets, spaced about 2 inches apart. Bake for 9-11 minutes until the edges are set but the centre still appears slightly soft.
- Immediately upon removing the cookies from the oven, gently press one unwrapped chocolate Kiss into the centre of each hot cookie.
- Allow the cookies to cool on the baking sheet for 5 minutes while the chocolate softens slightly, then carefully transfer them to a wire rack to cool completely and allow the chocolate to set.