Ingredients
2 large onions, sliced into 1/4-inch rings
2 sprigs rosemary
2 tablespoons olive oil
2 tablespoons balsamic vinegar
Salt and pepper
Preparation
In a bowl, toss onions, rosemary, olive oil, and balsamic vinegar; season with salt and pepper.
Transfer onions to hot wok, reserving bowl and marinade; cook onions, tossing frequently, until golden and caramelized, 20 to 40 minutes.
Return onions to bowl; toss with reserved marinade.