1. Preheat and Prep

Preheat your oven to 350°F (175°C). Line two baking sheets with parchment paper for easy cleanup.

2. Mix the Dry Ingredients

In a small bowl, whisk together the flour, cocoa powder, and salt. Set aside.

3. Cream the Butter and Sugar

In a stand mixer or using a handheld mixer, beat the softened butter on medium-high speed until smooth (about 1 minute). Add granulated sugar and continue beating for 2 minutes until fluffy and well-creamed.

4. Combine Wet Ingredients

Add the egg yolk, milk, and vanilla extract to the butter mixture. Beat on high speed until fully combined, scraping down the sides of the bowl as needed.

5. Incorporate Dry Ingredients

Gradually mix the dry ingredients into the wet mixture on low speed until a dough forms.

6. Shape and Coat

Pour the sprinkles into a shallow bowl. Scoop about 3 teaspoons of dough per cookie, roll into balls, and coat each ball thoroughly with sprinkles. Place on the prepared baking sheets, spaced 2 inches apart.

7. Bake

Bake for 10-12 minutes or until the cookies are set but still soft.

8. Add the Hershey’s Kiss

Remove the cookies from the oven and immediately press a Hershey’s Kiss into the center of each cookie. Let the cookies cool on the baking sheet for 5 minutes before transferring them to a wire rack to cool completely.