I made an apple pie the other day and peeled 6 or so apples. I ended up composting the peelings, and it got me wondering, what else could I have done with them?
You could use them, together with the core, to make apple-glaze (for your pie). Cover everything with water, simmer about 30 min, strain, simmer until you reach the desired density.
You can do something similar to how low-end vodka is made from potato peelings:
Take all the peels, stuff in a blender, and liquefy with as little water as needed to make a fairly liquid slurry. Dump into a large pot, bring to a boil, cover, cool. Dump into a fermenter, add yeast, wait a week, strain, add a clarifying agent, return to fermenter, let rest a week, distill, recombine with water/sugar/apple juice to flavor: bam, free applejack :)
This takes some know-how with respect to fermentation, and some effort to set up the fermentation, but if you have loads of apple bits (like from pressing cider from 6 or so bushels), it is kinda worth it for free booze from nature.
This isn't exactly a culinary use, but apple peel is apparently a very popular exfoliant.
The other day I stumbled across this recipe for apple butter that uses the peels. It's made from apples as well, it's not just the peels, but the author specifically mentions that she dumps any extra peels (i.e. from apple sauce or apple pie) in the crock pot in order to increase the yield.
I haven't tried to make it, but the photo makes it look pretty delicious.
There are some "creative" suggestions towards the bottom of this page. (dietary supplement, jelly, string, ...).
Apple peels combined with any citrus slices and/or peels, a cinnamon stick, some whole cloves, and some allspice makes a great potpourri. Cover with water and maintain at a very low simmer on the back of the stove. It makes the house smell homey and comforting from the minute you walk in the door!