I mixed the last scraps of raspberry jam with some garlic puree and Tabasco, and it made a really scrummy relish for the meat at dinner. Something in between plum sauce and cranberry sauce, with a bit of added zing.
Chop up sour apples whole, cores, peel and all - Bramleys or unripe garden apples are good - and simmer them in minimum water for 45mins or so. Mush and either strain (if you want clear jam with no apple taste) or seive (if you want to include the apple pulp in the jam). I can't remember the proportions exactly, which is probably why my raspberry jam set too firm, but I think it may be about 1 cup of apple liquid or pulp to 3-4lb of fruit. I chucked the lot in. About 8 cups. .