Preheat oven to 350 degrees.
Sit butter out to soften. This makes for an easier mix.
Prepare a baking sheet by using parchment paper or spray PAM cooking spray on it. Let sit.
In a large mixing bowl, beat together the butter and both sugars until creamy and smooth. About 2-3 minutes.
Add the egg yolk, vanilla, extract, and black food coloring. Beat to incorporate.
Sift together the flour, cocoa powder, baking soda, and salt. Add to the butter mixture and beat on low speed until just mixed in.
Roll mixture into balls using 1 1/2 teaspoons of the dough for each cookie. Place on cookie sheet and leave 2 inches between each cookie.
Bake for 10 minutes. Remove from oven and sprinkle your sugar crystals and push a Mellocreme pumpkin in the middle.
Allow cookies to cool on a baking sheet for approximately 3 minutes and then move to a wire cooling rack.