Sweet-tart white balsamic vinegar and tangy Peppadew peppers bring flavor and color to this weeknight chicken dish. White balsamic, which is not cooked and aged as long as regular balsamic vinegar, has a mellow acidity that complements the Peppadews, a variety of small, sweet peppers from South Africa. They add slight heat and additional sweetness, as well as a vivid splash of red. Find them jarred at most grocery stores, and sometimes loose at the olive bar. When reducing the sauce before serving, add water if the liquid is less than 1 cup. Serve with roasted sweet potatoes, boiled baby red potatoes or spinach pasta tossed with butter and poppy seeds.