This can be served as part of an antipasto, or as a side dish to accompany a roast. Use good quality, black dried olives tostate, or toasted — as they are sold in Tuscany — or drained, black olives in brine or olive oil. Seasoned, they will only last a couple of days in the refrigerator, as they are not immersed in any liquid. The orange and lemon zest bits look lovely against the shiny black olives.