Comfort food conjures up images of creamy mashed potatoes, steaming bowls of rich soups, and juicy, gravy-topped roasts. But in the past two decades, this Sunday-family-dinner kind of cooking has become less appealing as the public leans more toward healthier fare. Sue Spitler says readers can still enjoy the foods of their childhood, and proves it with a collection of recipes for more than 100 memorable family favorites. Illustrations.