This is a lovely appetizer when served with crostini, pita bread, bagel chips or crackers. I've also used it as a topping over a salad of mixed greens. This mushroom version of a caponata is a twist on the traditional eggplant one.—Julia Cotton, Pacific Palisades, California

To make ahead: Can be made 2 days in advance. Reheat over low when ready to serve.