the preemptive notes, in the lead-up to the actual recipe:
- this is very easily adapted. use whatever juice you like, or just water if you care only about a pure "ice" look and not so much about any nutritional value. after some earlier experiments, however, i do urge you to stick to using a sand castle pail and not the smaller sand-castle forms out there, since the pails stand solidly flat on their own. i tried some cute little forms during a trial run, propping them level with an assortment of napkins and wash clothes and office clips. good night. all that, and they didn't really work. also, even if your chosen forms can stand on their own, be sure to check for small holes (actual sand castle forms typically have them for water to drain out, and gelatin will drain out just as easily!). wash in your dishwasher before use to sanitize. mine held up fine, even on the bottom rack.
- how big a pail? this recipe is based on a sand castle pail i bought at the dollar store. i eye-balled the size compared to past gelatin adventures and, remarkably, estimated correctly. in this case, four 9-by-13 pans worth of gelatin snack recipes (think knock-off Jell-O) filled this pail perfectly. if you end up with too much, add the leftovers to a pan and let firm up in the refrigerator as some extra snacks. if you end up with too little, it's no problem to mix up some more and add to the top. gelatin is very forgiving.
- the color of your sugar crystals matters. i expected the blue sugar crystals to keep their exact look suspended in the gelatin. however, as soon as colored sugar gets wet, all the color comes off. in our case, this ended up creating a very cool blue-green effect when mixed with the slightly yellow white grape juice gelatin mixture. it was a happy accident and ended up turning out better than i had envisioned.
- deciding when the gelatin is "semi-firm" is a tricky business. what i suggest is doing things in waves. check at the first hour by sprinkling some sparkles on the surface. they will very likely sink right away, which means it's not technically semi-firm yet, but you're still adding some nice additions to the top of your castle, which you won't be able to reach by the time it is all semi-firm anyway. after the first hour, repeat every half-hour until you're satisfied with your additions. by the end, you'll be using the handle of your spoon to depress the additions into the mold by only a couple inches. don't worry about hole-poke marks; the gelatin will ooze back over itself if it's still semi-firm, like some kind of primordial goop. which leads to the next consolation: this is a very forgiving stage of things. don't really have time to check every 30 minutes? don't sweat it. gelatin knows no stopwatch, especially when it's this big a batch.
- the finished product can tend to be rather "runny," especially when dealing with a larger batch like this. if i had to do it again, i would have put a clean white rag down flat on top of the serving tray and invert the mold on top of that. it would still look like "snow" and serve the double purpose of soaking up some of the runny liquid so that the confectioner's sugar doesn't dissolve into a soupy mess. as an easy alternative, though, just do what i did and add the confectioner's sugar at the last moment.
- make room in your refrigerator if you can manage it so that the empty pail mold and tray can be set on a shelf with enough head space above to pour the liquid in and, later, stir in the additions. the less you have to move the pail o' gelatin, the better. trust me. let's just say i was up until 12:30 a.m. after spilling one-quarter of this mixture on the floor during one of the more involved addition-stirring rounds. the upside? if you do spill some, it's easy enough to mix up more gelatin mixture and add on top of what didn't spill out with no ill consequence. a dessert that forgives as well as tastes and looks good? thank your birthday stars, mommas!
Gelatin "Ice Cake" recipe
16 packets gelatin (about 16 T)
120 liquid ounces white grape juice (e.g., one 96 oz jug, plus 24 oz bottle)
Additions of choice: we used blue sugar crystals and clear, sparkly sugar sprinkles
Sand castle pail form (dollar store size used in this recipe)
Serving tray or cake stand
Note: The making of the gelatin itself follows the basic recipe for making four batches of gelatin snacks, decreasing the liquid by 1/4 cup per batch, so 1 cup less liquid total.
1. Heat 11 cups juice to boiling.
2. Meanwhile, pour 4 cups juice into a large bowl. Sprinkle gelatin over top and let stand to soften while the other juice boils, 1 minute or more.
3. Set the pail on a tray and position in or near the refrigerator (see notes above). Coat interior of pail well with cooking spray.
4. Add hot juice to gelatin mixture. Hand-stir for 5 minutes.
5. Pour mixture into pail mold. Refrigerate.
6. Check firmness at one-hour mark, then every hour or half-hour beyond that (see notes). Add additions as desired. Gelatin is semi-firm when additions sit on top of the mixture but you can still use the handle of a wooden spoon to poke the sprinkles and crystals down into the mixture.
7. Continue to refrigerate for 3 hours or overnight.
8. Invert pail of gelatin cake onto serving tray or cake stand, on top of a white cloth if available (see notes). Sprinkle confectioner's sugar around the castle like snow. Sprinkle more sparkly sprinkles or blue sugar crystals over top of confectioner's sugar and castle, as desired.
i set this castle on our kitchen table, where we were going to put the food. this room happens to have some tall windows, and the effect was gorgeous. it sparkled all on its own! if you don't have the advantage of natural light indoors or a sunny day outdoors, consider sticking a little battery-powered LED light into the bottom. that was my back-up option. if you try it, please please please leave a comment to let us know how it worked...
to add a candle on top, i stuck the pointy end of a wooden skewer into the bottom of the candle, broke off the skewer to length and gently impaled the castle. it worked quite well. and, more important of course, it was a special request by Sweet One.
the self-conscious blogger in me would like to note that i had ordered some high-quality gelatin and colored sugar online but it didn't arrive in time. that said, Winco and Wilton's worked just fine. anyone who's done research on gelatin or had more experience with large batches of different varieties, please share your findings in the comments! (also, have I ever mentioned that i think the cow is the greatest animal on earth?)
below you'll find affiliate links to some of the products i recommend for Amazon shoppers looking to replicate our "Frozen" gelatin ice cake and other party features: