Preheat the oven to 350 degrees. Line a large cookie sheet with parchment paper. Set aside.
In a medium bowl {or the bowl of a stand mixer} beat together butter and sugar until fluffy. Add egg yolk and vanilla extract; mix until fully combined.
Add cocoa powder, flour and salt. Mix until the dough just comes together -- do not overmix.
Using a cookie scoop or spoon, scoop out about 1 ½ tablespoons of dough. Roll into balls, then place onto prepared baking pan at least 2 inches apart.
Bake for 14-15 minutes or until the cookies are set. {They will still feel soft to the touch, but will harden as they cool.}
Remove from oven. While the cookies are still warm use the back of a ½ teaspoon measure, the end of a wooden spoon or your thumb, to gently press a well into the center of each cookie. {They might crack a little, just press them back together gently and they should be ok.} Allow to cool completely.
Meanwhile, make the filling: In a small bowl, cream together the cream cheese, butter, powdered sugar and vanilla until completely smooth. Scoop the mixture into a piping bag or a zip top bag with one tip snipped.
When the cookies are cooled, fill the well of each cookie with the cream cheese filling. {You may have a bit left over.} Gently press a fresh raspberry into the center of each cookie.
Place the melted chocolate chips into another piping or zip-top bag with the tip snipped, and drizzle over each cookie. Allow the chocolate to set before serving. {You can refrigerate for about 10 minutes if you need to speed up the process}
If you won't be serving the cookies right away, refrigerate for up to 6 hours, then bring to room temp when ready to serve.