If you want sugar pieces that aren’t shaped like cubes, pour the sugar into oven-safe candy molds or muffin tins. If you have candy molds that aren’t oven safe, you can still use them. Pour the sugar into the molds and use a spatula to flatten the tops. Instead of putting the molds in the oven, cover them loosely with parchment paper and leave them on the counter overnight. They’ll be hard by morning.
At this stage you can mix in a few drops of food coloring to make colored cubes. Consider adding a few drops of vanilla, almond, or lemon extract to make flavored sugar.