You probably want to make an afternoon of this and make ALOT. This is kind of a pain in the rump but if you have raw kids it might well be worth it. After-all raw kids deserve some stars and hearts in their buckwheaties now and again :)
mini cookie cutters
apples, mangoes, melons, etc.
strawberries make good hearts
Slice your fruit into thin sheets. A mandoline can be a timesaver here but doesn’t work well on all fruits. Strawberries slice into great pre-fab hearts, for the other fruits use your mini cookie-cutters to cut out different shapes. (There are tons of different sets you can find online) Don’t throw away the scraps! They usually look like funky stars Weeeee!
You can dip them briefly in a weak salt/lemon solution to keep them from turning brown but I usually omit that. Dehydrate (105 degrees) your shapes until chewy and not too shriveled. This seems to totally depend on your humidity and personal taste but I usually do this at night and they are done in the morning 8-10 hours.
Now hide them cuz “the kids will be after your Lucky Charms”! Serve a handful over buckwheaties or your favorite gRAWnola.