1. Place chocolate in a small microwave-safe bowl. Microwave on medium for 1 minute, stirring once halfway through. Stir until smooth and melted. Let cool for 5 minutes.
2. Meanwhile, combine butter and granulated sugar in a mixer bowl; beat until light and fluffy, about 3 minutes. Add egg, corn syrup and vanilla; beat until well combined. Scrape down sides of bowl. With mixer on low, add flour, cocoa and salt; beat until combined. Stir in melted chocolate and mix until well blended.
3. Divide dough into 2 disks, wrap and refrigerate for 1 hour or up to 2 days.
4. Heat oven to 350 degrees . Line baking sheets with parchment paper. Roll dough between 2 sheets of wax paper to -inch thickness. Cut dough into 3-inch circles, using a cookie cutter. Place on prepared baking sheets, 1 inch apart, and bake at 350 degrees until edges are just lightly browned, about 10 to 12 minutes. Cool on baking sheet for 2 minutes. Transfer cookies to a wire rack and cool completely. Repeat with any remaining dough.Royal Icing
5. Place confectioners' sugar and meringue powder in a bowl with mixer fitted with a whisk; beat on low to combine. Beat in 1/4 cup water; increase speed to high and beat until stiff peaks form, about 3 minutes. Add an additional 2 tbsp water and beat until light and fluffy.
6. To decorate, place 1 cup of the icing in a bowl and tint with black food coloring. Transfer to a decorating bag fitted with a #4 writing tip.
7. Dilute remaining white icing with 1 tsp water at a time until it has the consistency of thick heavy cream. Decorate cookies as desired.