Balsamic Caramelized Onions

• 1 tablespoon olive oil
• 2 large yellow onions, halved lengthwise and thinly sliced crosswise
• 2 tables

In a large frying pan over medium-low heat, warm the oil. Add the onions and cook, stirring every so often, until they soften and start to brown, about 10 minutes. Reduce the heat to low, sprinkle the onions with the vinegar, sugar, and a pinch or two of salt, and continue to cook, stirring occasionally, until the onions are richly browned, about 30 minutes. Add a little water if the onions dry