After I sent the prompter copy of "Chamomile and Honeycrack" to westrider, we got into a discussion of traditional candymaking. Yes, I drew inspiration from real candy, and I've made both hand-pulled taffy and hard candy of this general type. Here are my notes from that conversation ...
I based the description of honeycrack on a category of oldstyle candy called "crack" or "crackle" that was made that way using such things as sugar, molasses, honey, or maple syrup as a base. So "maplecrack," "molasses crackle," etc. It was also sometimes called "snow candy." It'll work on finely crushed ice such as for a snow cone, but you need to have a smoothish surface to pour the syrup over so that it will set properly and can be picked up. Larger crushed ice doesn't work as well.
When I looked up recipes, I discovered that some versions seem to make taffy while others make hard candy. It may vary based on ingredients and cooking times. Try comparing different recipes.
Maple Sugar Taffy
Molasses Hard Snow Candy
Hard Crack Snow Candy
I had a devil of a time finding actual honey candy recipes -- there aren't a lot of oldstyle hard candy recipes to begin with. Often people would make candy from crystallized honey as a way to use it up, and that's not the kind of thing that often gets written down. I did find this one for a "hard ball" stage honey candy that might crack nicely if cooked hotter.
Also the kind of hard candy recipe that tells you to pour it into a pan and "work fast" to cut it will usually adapt to being poured over snow, where you get the crackle effect.
Basically the candy syrup has to be cooked to the "hard crack" stage, which is what makes it crackle when cooled abruptly. Yes, it really makes noises when it cools that fast, hence the sound effects in the poem. Kitchen chemistry and physics are so much fun!
WARNING: Boiling candy syrup is extremely dangerous. It is like homemade napalm. When it's fully liquid it can bubble up or splash and get on things or people. When it's thicker, it clings to everything and is almost impossible to get off. Don't touch it with your bare hands, even a little, until it has cooled down enough to be safe. A good pull-taffy recipe will tell you how to determine when the stuff is cool enough to handle. Don't poke cooling candy with your finger to test its heat either, although if it's not moving you can hold your hand above it for that. Preferably, use a candy thermometer and/or the physical tests. Here is another nice guide to stages with photos.
If you make candy from syrup, you have to be super careful, so I don't recommend it for kitchen novices or small children. A determined and meticulous intermediate cook can handle it, and an experienced cook should to fine; it's not really difficult, just risky. Older children are okay as long as they know how to behave in a kitchen and there is close adult supervision.