Heat oven to 375º. Grease or spray a mini muffin tin with cooking spray.
Combine orange zest and sugar in a small bowl. Cream the butter and cream cheese until well combined.
Add the orange sugar, salt, and vanilla, and blend until ingredients are well combined, but not fluffy. Add the flour and mix just until incorporated.
Fill each muffin cup with 1 tablespoon of cookie dough. Bake 10 to 12 minutes until edges are browned, the centers will not be completely set. Remove the cookies from the oven and using the end of a thick-handled wooden spoon make a small, deep well in the center of each cookie. Remove to a wire rack to cool.
Cream Cheese Frosting
Cream the butter and cream cheese together. Add the powdered sugar and beat until light and fluffy.
Pipe the frosting into the cookie cups (I used a ziploc bag with the tip cut off) or spoon it in. Drizzle with the melted chocolate. Put into the fridge until ready to serve.