When I first began making this delicious condiment, I used big red torpedo onions. Today I am just as likely to use locally grown Walla Walla onions or whatever other big sweet onions are available at a farmers market. The most important thing is to use onions with a high sugar content. If, after lengthy cooking, your onions takes a bit flat, without any sweetness, consider sprinkling a tablespoon or two of granulated sugar over the onions a few minutes before adding the liquids.
Red Onion Marmalade, by request
A reader contacted me, saying she'd lost her copy of this recipe and asking if I still had it. Of course I do! Here it is, for her and for you.
Directions
Put the butter into a large, heavy skillet set over low heat and, when it is melted, add the onions, turn to coat them all with butter, and season with salt.
Cook very gently until they are very limp and have released their sugar, about 45 minutes; stir now and then as the onions cook.
Increase the heat to high, add the wine, vinegar, and creme de cassis, bring to a boil, reduce the heat to medium, and simmer until the liquid is nearly completed reduced to a bit of thick syrup.
Remove from the heat, cool slightly, taste, correct for salt, and season with several turns of black pepper. Enjoy right away or store in glass jars in the refrigerator; it will keep for up to 10 days.
I prefer a full-bodied red wine vinegar, one from O Olive Oils & Vinegars or B. R. Cohn, perhaps, but you may also use a balanced balsamic vinegar. Try to find one that is not overly sweet, as some made in the United States are.