From the recipes... Is this a crusting icing?

1 stick butter, softened
1/2 cup unsweetened cocoa powder
1/2 cup chocolate syrup
3 cups confectioners' sugar, sifted (measure out 3 cups first and then sift)
1 tablespoon milk (whole or 2% preferred)
1 teaspoon vanilla

Place the butter, cocoa powder, and chocolate syrup in a large mixing bowl. Blend on low speed until just combined. Add the sifted sugar, milk and vanilla and blend on low until the sugar is combined. Increase the mixer to medium-high speed and blend 1 minute longer, until smooth and spreadable. Add a little more milk or sugar if needed.