Heat oven to 350°F. In large bowl, with electric mixer on medium, beat butter, powdered sugar, vanilla, and salt until just combined. Beat in cocoa, then flour.
Divide dough in half, and pat each portion into a 7-inch circle on a large baking sheet. Score each circle into 12 wedges. Bake 30 to 35 minutes, until firm.
Cut along scored lines into wedges while still warm. Transfer wedges to wire rack and cool completely.
Microwave morsels on medium-low for 1 minute, stirring halfway through. Repeat a few more seconds until melted. Place a sheet of waxed paper under wire rack with cookies for easy cleanup. Using fork, drizzle melted morsels over cookies and sprinkle with dragees, if desired. Remove dragees before eating cookies.