Vidalia, Walla Walla, and Maui onions, to name a few, have a short availability season, but it’s a sweet one. And with the season in full swing right now, take advantage of them while you can. In the case of onion jam, the onions become even sweeter as they cook down. This recipe is flexible because you can make either a white or a red wine version — both are equally delicious. Serve jam with cheese, as a spread on sandwiches or as a topping for meats.