Use this as you would apple butter or applesauce. You can poach the quinces in just water, without any sweetener, and add sweetener once the quince butter is ready. This way you can adjust the sweetness to your preference.
2 lbs quinces
1 1/2 c water
6 T sugar or 4 T honey, or maple syrup, or agave syrup
1. Peel quinces. Halve, core, then cut into smaller slices, or not. You can also cut the quinces up first and then peel. Combine quinces, water, and sugar or other sweetener, if choosing this method over that in the headnote. You can also put the peels, cores, and seeds in a cotton bag and add to the quinces. This will give the butter more body, as the majority of the pectin in quinces is in the core. Just remember to remove it before serving…
2. Simmer for a couple of hours. This will give you a butter. If you would be content with a quince sauce, or compote, then simmer for about an hour, until very tender.
3. Remove mixture from heat and either mash with a potato masher or immersion blender in the pot, or put through a sieve. If you’ve made this without sweetener, add some now.
4. Refrigerate, covered.