I don't have a corer but I had a tiny lemon oil lid about the right size. you don't need to core every slice, just the tougher parts that already begin to look brown as you approach them after slicing. I love the look of the slices that don't require coring, they look like little flowers! Here are some slices that were cored and one that didn't require it:
They're pretty both ways :)
To be clear, you should toss your slices in to soak as you core them, then soak while you prepare cookie sheet and rack and
If you're going to add cinnamon or a mixture of that, nutmeg, and sugar, now is the time to prepare this in a bowl, and rub it on each apple slice as you place evenly on a cookie sheet.
Ready to pop these babies in the oven!
Stick the handle of a wooden spoon between the oven and it's door for some air circulation.
set the timer for 18-20 minutes and flip slices over, replace in oven with wooden spoon prop, and bake for another 18-20 minutes and repeat as you see slices golden and curl around edges until brown and woodlike, but not burnt! Here are some more pictures!