In a big bowl, combine the sugar, meringue powder, and then the water. If you want to color your skulls, add the food coloring to the water. The sugar mixture should clump together in you hand like damp sand, not crumble away or feel wet.
Push the sugar mix into the mold and scrape off the excess with the cardboard. Place the cardboard onto the back of the skull mold and flip. Lift the mold and if the skull cracks or crumble a bit, just put it back in the mold, press, and flip again. Let the skulls dry until hard, about eight hours for large ones.
Tip: It's really hard for the sugar to dry in humid or wet weather, so if it needs a little help, warm your oven up on the lowest setting, turn your oven off, and let the skulls dry out in the oven.
To fashion both sides of the skull together, use royal icing as the glue. Decorate with sprinkles and different colors of icing. To make the white chocolate studs, take chocolate chips and shave for hard edges with an exacto knife. Put the studs in a baggie with edible silver dusting powder and shake to coat.