No need to squeeze oranges for this recipe, as the sweetness and body of store — bought juice are key. If you cook the mixture down until most of the liquid is evaporated, you’ll end up with a delicious onion confit rather than a sauce. Either way, we like to serve this with grilled meats and chicken as well as fish.

Ingredients

　　1 medium red onion

　　1 cup orange juice

　　1/2 cup balsamic vinegar

　　1 to 2 tablespoons sugar

　　Halve onion through root end and cut crosswise into very thin slices. In a 1 1/2-quart heavy saucepan simmer onion with orange juice and vinegar, stirring occasionally, until liquid is reduced and thickened, 30 to 40 minutes. Stir in sugar and salt to taste and cook mixture over low heat, stirring, until sugar is dissolved. Serve sauce warm or at room temperature.