I had a lot of green tomatoes this year, thanks to early blight. The plants had died, and the tomatoes would have rotted if I'd tried to let them ripen, so I chopped them up before the blight affected them. I like to make green tomato mincemeat from my great-grandmother's recipe, and I made a large batch, but I still had 4 pounds of green tomatoes left, and I really didn't need any more mincemeat, since I had plenty for a couple pies for each of Thanksgiving and Christmas.
I went looking for alternative uses for the tomatoes and came up with green tomato jam. It's sort of like ginger-flavored honey with bits in. (I love the British "with bits in" phrasing, and it seems appropriate, because the jam has a passing likeness with marmalade, a Brit favorite, which has citrus bits in.)
Here's what I did, modified by what I wish I'd done (namely, use a food mill, which I don't have, to remove the seeds and get a smoother texture for everything except the lemon peel):
2 lb green tomatoes, chopped (and de-seeded if you don't have a food mill) and frozen, then thawed and thoroughly drained overnight to remove excess liquid. Toss the liquid (or use it to water the garden).
2 cups sugar (might start with half of this, to see if it's enough, and only add more toward the end, if necessary)
1 cup cider (to replace the tossed liquid and add some pectin)
1 stick cinnamon, broken in half
1" piece of ginger root, peeled and diced into tiny bits
Toss all of these things into non-reactive pan and bring to a boil for a few (maybe three to five) minutes, just to heat everything. Cover and let sit for several hours (or overnight) to absorb the ginger flavor.
This is what I didn't do, but wish I had: run through a food mill to remove seeds and skins. Alternatively, if you removed the seeds before freezing the tomatoes, then you could whirl the partially cooked stuff in a food processor until reasonably smooth. There would still be some skin bits, but that's okay.
Return to pan.
Take 1 lemon, and peel the zest (just the yellow part, not the white part). Cut the zest into itty-bitty pieces.
Add the lemon zest and the juice of the lemon to the tomato mixture. (You could do this before the first cooking, but I like the texture of the little lemon bits, sort of like marmalade, so I prefer to keep them intact, not pureed.)
Bring it to a boil and just keep boiling it until it reduces by at least a third, possibly more. It never really gelled like jelly, but reached the texture of warm honey, and when it cooled it was a little more solid, like cold honey or cold molasses. Process or keep refrigerated.
It's EXTREMELY sweet. Really, a lot like honey. The sugar could be cut back. I cut it down from the original recipe, but I added cider, which is also pretty much pure sugar, so I should perhaps have cut back even more on the refined sugar.
The places where I found the recipes to get me started all suggested using it with cream cheese on crackers. I do think it would be best with something savory to balance out the sweetness. I haven't quite figured out how I'm going to use mine, because I'm not much of a cracker eater.