This onion relish is one of those treasures to have handy in the refrigerator. It can be used so many ways-part of a vegetable dish, as a topping or relish with meats and top burgers, chopped up and mixed into whole grains, as part of a soup, and they are especially good mixed with roasted or grilled peppers. This makes a great base for pastas and sandwiches.
Take your time the first time you make this and pay attention to the process. Once you do it a couple times you can play around with it. Use higher heat to cook it faster, use thinner or thicker slices of onion for a different texture, experiment with other onion types and different vinegars. Try different herbs in these as well. I usually make these while doing other things in the kitchen, like making tapenade or Romesco sauce, or cleaning lettuces and making dressings.
3 large brown onions, peeled and sliced into 1/8 inch thin crescents
2 tablespoons olive oil
1-2 tablespoons good quality balsamic vinegar
1 smallish pinch salt
Water as needed
Heat a heavy-bottomed saucepan that is large enough to hold all the onions over medium-high heat. When the pan is hot, add the oil. When the oil is hot-it should seem to be shimmering in the pan-add half the onions.
Stir the onions around and coat with the oil. Cook, stirring fairly often to prevent burning. When the onions have cooked down a little, add the rest of the onions. Stir the onions around some more to ensure all the onions get oiled.
Continue cooking the onions, stirring frequently to avoid burning and ensure even coloring.
When the onions begin to lose a lot of their volume, and are turning golden, reduce the heat to as low as you can get it. Continue cooking the onions slowly so they caramelize and get really soft. Cook the onions are sweet and golden-brown. If it seems they are sticking to the pan bottom, or scorching, add 2 ounces of water to the pan and cook a little more.
Add the balsamic vinegar to the pan and the pinch of salt, stirring to coat all the onions. Cook down to a syrup. The onions should be quite soft, sweet, and deeply colored. Remove from the heat and transfer to a bowl or jar to stop the cooking and avoid burning the onions. When cool, transfer to the refrigerator or use right away. Should around a week in the refrigerator.
CHEF NOTES: Once you are familiar with the process, you can speed it up by turning up the heat in the pan and tossing the onions frequently at first. Then turn down the heat a little, add a shot of water to the pan and cover it with a tight-fitting lid. The steam in the pan will cook the onions faster and help sweat the liquid out. Check frequently for scorching, using water to stop this from happening. When the onions are wilted all the way, remove the lid and sauté to onions to color them. Then add the vinegar and proceed as above. Using the water judiciously allows you to cook these faster.
YIELD: 1-1½ cups of caramelized onions.
SOURCE: Chef Andrew Cohen