Slow roasted plums add a great tang to salads, replacing the need for vinegar. Damson plums are especially sour and great for this use. Simply slow roast the plums on a cookie sheet lined with aluminum foil at 250ºF for one hour, until they are soft and have released a nice puddle of juice. Use the juice as vinegar, and toss the plums into the salad. Plums go great in salads combined with goat cheeses (both hard and soft).