Recipe for "Quince Paste" from "Ripe: A Cook in the Orchard" by Nigel Slater. I made 1/2 the recipe (4 quinces); I think that this is a good size to make. If I had made more then this, then the quinces would be hard to fit into a pot, and it would make way more quince paste then we could eat.
Although I'm happy with the result I got, I don't think Slater is precise enough about the steps in the recipe and I had to tinker with the recipe a bit. Slater first poaches the quinces in water, however he doesn't specify if the poached quinces should be drained or not before they are pulverized in a food processor or blender. This makes a difference for two reasons. First, he has you add half the weight of the pulverized quinces in sugar; since the amount of water that you poached the quince in is variable (depending on the size of your pot and how much evaporates), measuring the water will cause variable amounts of sugar to be added. Second, the latter part of the recipe is to evaporate all of the excess liquid in the quinces, so not draining the quinces will cause a longer cooking period.
Since he didn't say to drain the quinces, I kept the water, but my cooking times were much longer than he suggested. Since the 20 minute poaching period that he suggested last time I cooked quinces was way to short, this time I poached my quinces for 1 hour, until they could be cut with a spoon. Passing the pulverized quince paste through a sieve didn't really seem to take out any particles for me, so I think this step can be skipped. It took about an hour to dry out the pulverized quince and water paste. This whole time the paste had to be stirred since Slater says that it tends to sputter up if it isn't stirred. Even though Slater complains that this is a laborious recipe, I found most of the recipe easy and didn't require much effort, though this stirring was the only fussy and tedious step. I also had to dry out my paste for nearly 8 hours in the oven before it would set most of the way through, instead of the suggested 3 hours. Slate also didn't specify how low your oven should be; he just said to use the lowest setting. My oven's lowest temperature is 200 F; this temperature was fine to use for me for extended drying.
This recipe by Alex Kingston is more precise, and it does suggest draining the quinces, so I think that you are actually supposed to drain the quinces. This would give much shorter cooking times, but if you don't want to waste the flavor in the cooking water and you are patient, then you can also use the poaching water.
I also added a teeny tiny pinch of salt to the quince paste to help bring out the flavors, but not enough to taste it.
The quince paste will set more and become slightly firmer once it has been in the fridge for a while, so don't worry if the bottom of the paste hasn't set when it comes out of the oven. It will most likely firm up once it has been in the fridge for a few hours or overnight.
Peeled, quartered, and cored quinces just as they begin to poach:
Pulverized quince paste, after cooking for about an hour:
The set quince paste, after being dried in the oven for a few hours:
From top left going clockwise: bread, Petit Basque sheep's milk cheese, pecorino romano, Arte Queso raw milk manchego, quince paste, and Olympic Provisions chorizo rioja (a spanish style salami with sweet & smoked paprika). We loved the Petit Basque cheese best!