Place ham on a rack in a shallow roasting pan. Bake at 325° for 1-1/4 to 2 hours or until a thermometer reads 140° and ham is heated through. , Meanwhile, in a saucepan, combine 1/4 cup water, brown sugar, soy sauce, ketchup, mustard and pineapple. Bring to a boil. Reduce heat; cover and simmer for 10 minutes. Combine cornstarch and remaining water until smooth; stir into pineapple sauce. Bring to a boil; cook and stir for 2 minutes or until thickened. Serve with the ham.