French gastrique is, essentially, a sweet-and-sour sauce. The primary flavor (and some of the sweetness) typically comes from fruit and the sour, from the vinegar. Easily made with butter, shallot, fruit, sugar, wine or cognac, and vinegar, it's a great sauce to keep on hand. The beauty of a gastrique is its versatility. With this one simple recipe, you can create endless flavors and experiment with different fruit and meat pairings to see which you enjoy most. You will find that this sauce is an amazing addition to roasted or sauted pork and poultry dishes.