I have tried this several ways with no luck, or minimal luck. I have tried pouring the Isomalt over Ice and letting it melt and it got chalky
The best luck was pour the isomalt over tin foil that had been cumpled up an lettign it dry and break with a hammer, works good, but not the look I want. I want it to look like little ice cubes like you buy in the bag,
If you want something that even, you need a mold. I use silicon ice cube trays, some people use the Wilton silicon brownie molds. You'll still need to do some torching when you're done, as the silicon will gas when the isomalt hits it.