I planted a japanese quince plant this spring, and lo and behold, there are now japanese quinces growing on it! (I bought it because it was a flowering shrub - I had no idea I'd have fruit in the first year, if at all). All recipes I can find only refer to regular quinces - does anyone know if japanese quinces are interchangeable with regular ones in recipes, and how can I tell when the quinces are ripe? Help!
They're not interhangeable, but the Japanese ones make superb preserves. Your question takes me way, way back to my starving student days when the student house I rented a room in had miniature ones as a border around the yard. My landlord never sprayed so I picked them (they only grow about 1-1/2" in diam.) quartered and cored them and cooked them up w/ a lot of sugar b/c they're very sour.. It's important to leave the skin on b/c it has a wonderful, spicy aroma. They are full of natural pectin, so there's no need for any additional. It was the first time I learned to sterilize mason jars (which I borrowed from a friend). It was a lot of work, but so worth it.
I guess you could add some nuts and maybe ginger, use a little less sugar than you would for ordinary preserves and use it as a chutney, but the natural flavor of the skin--sort of clovey and allspicey--shouldn't be drowned out, IMHO.