Noel and I spent two days making a giant pile of quince paste. This is not recommended as a regular activity, unless you want to build really burly arms. I will describe the process in less than perfect detail:
Wash and dry quince, then roast in covered pans for an hour and a half or so. Here we have two of our three roasting pans of quince. Num.
The other option is to peel and core the quince then boil the heck out of them, but that seemed like a lot of work. Once the quince were roasted, peeling was basically irrelevant, though you can still peel them if you want, and coring was easy.