Remove meat from package, reserving juices. In a large skillet cook shallots in hot margarine or butter over medium heat for 1 minute. Add pot roast; reduce heat. Cover and simmer about 10 minutes or until pot roast is heated through.
In a small bowl stir together reserved meat juices and tarragon vinegar. Pour over meat. Toss fruit over top. Cover; heat for 2 minutes more. If desired, serve with cooked spaetzle. Top with snipped tarragon. Makes 4 servings.