Preheat the oven to 350°F (175°C). Prepare two baking sheets by lining them with parchment paper.

In a mixing bowl, cream together the butter with both sugars until the mixture is light and creamy, about 2-3 minutes. Add in the egg yolk, vanilla, and red food coloring. Mix until combined.

In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.

Gradually add the dry ingredients to the wet ingredients, stirring just until the dough forms, without overmixing.

Shape the chilled dough into 18 small balls. Roll them in the sanding sugar. Place the dough balls on the prepared sheets, spaced about 2 inches apart.

Bake the cookies for 8 to 10 minutes.

Remove baking sheets from oven and immediately place a Hershey's Kiss in the center of each cookie, pressing down just slightly. Cookies will crack slightly around the edges.

Let the cookies cool on the baking sheet for 2 minutes, then transfer them to a wire rack to cool completely.