Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper.
Cream the butter and brown sugar in a large bowl with a hand mixer until light and fluffy, about 2–3 minutes.
Add the vanilla, egg, egg yolk, and red food coloring; beat until the color is evenly incorporated and the mixture is smooth.
In a separate bowl, whisk together the salt, flour, baking powder, baking soda, and cocoa powder until combined.
Add the dry ingredients to the wet ingredients in two additions, mixing after each addition until just combined.
Place the granulated sugar for coating on a shallow plate. Roll the dough into 1-inch balls, then roll each ball in the sugar to coat.
Arrange the coated dough balls about 2 inches apart on the prepared baking sheets; this recipe yields about 48 cookies.
Bake for 11–13 minutes, until the edges are set but the centers are still slightly soft; avoid overbaking to keep cookies tender.
Immediately after removing the cookies from the oven, press a Hershey's Kiss into the center of each cookie. Transfer to a wire rack and cool completely.