tablespoons olive oil
pounds yellow onions, peeled, trimmed, halved and thinly sliced lengthwise. ( about 9 pounds)
Heat the oil in a 12 inch skillet over medium heat until hot, about 1 minute. Add the onions, sprinkle with the salt and cook, stirring frequently, until they wilt completely and begin to stick to the bottom of the pan, 10 - 12 minutes (much of the onions' moisture will evaporate and the pan will begin to brown; the cooking time varies with the onions moisture content.) Reduce the heat to medium low and cook, stirring and scraping the pan with a wooden spoon every few minutes. (If the pan begins to look like it's burning, add 2 tablespoons water, stir, and lower the heat a bit). Cook, stirring and scraping and adding water as needed, until the onions are a uniform caramel brown, another 30 to 45 minutes. If they haven't begun to brown much after 20 minutes, raise the heat to medium.) Add a couple of tablespoons of water and scrape the pan well. Use right away or let cool to room temperature. Store covered in the refrigerator for up to one week. Can freeze for 2 months.