We love vidalia onion relish on hamburgers, but haven't had it in the house lately. This recipe is an adaptation of Bert Greene's Onion Marmalade from his wonderful book Greene on Greens. (It was published in 1984, but it has great ways to use all sorts of vegetables. It's one of my favorite cookbooks.) His marmalade is an homage to Michel Guerard's conserve, and I've taken quite a bit of license with it. Because I wanted to use it to cut the richness of meat, I did not add butter to mine. (He uses a full stick.) And with sugar, honey and prunes, I thought his would be way too sweet for my taste, especially since vidalia onions are sweet to begin with. I also wanted to give the dish some heat. My favorite ways to use this so far have been spooned onto crackers and on a sandwich of grilled Gruyere on whole wheat bread. I think it would be a great filling for an omelet, and of course with ketchup on a hamburger. (I'm also thinking of stirring it into cottage cheese, but that's just me.) —drbabs
Heat the orange juice over medium heat in a large skillet. When it starts to bubble a little, dump in the onions with the kosher salt, and stir till blended. Reduce the heat to low and cook covered for about 30 minutes.
At this point, the onions will have given off some more liquid and will be translucent. Add the sugar, allspice, ginger and mustard, stir well, cover and cook on low for another 15-20 minutes, when the onions will be browning and the liquid will be starting to reduce. Add the lemon juice, stir well, and sprinkle a dusting of cayenne. Cover and let the mixture cook for another 15 minutes or so.
Stir in the orange zest. Taste and adjust seasoning as desired. You can serve it at this point, or let it sit at room temperature so the flavors meld together more. Store it in an airtight container in the refrigerator; it should keep for a week or two if you haven't eaten it all by then.