T. unsalted butter
large white onions, thinly sliced
small sprig fresh rosemary or thyme
T. balsamic or sherry wine vinegar
Pinch of sugar, or to taste
Salt and freshly ground black pepper, to taste
Melt the butter in a large, deep saucepan over medium heat. Add the onions and the rosemary or thyme, spreading them out as thinly as possible, so they brown evenly and are less likely to steam. Coo, stirring occasionally, until onions are very soft and beomce golden, about 35-45 minutes(the darker they become, the richer they will taste). Discard herb sprig. Use in dishes calling for caramelized onion.