1 (4 to 6 lb.) fully cooked boneless ham
1/2 c. chopped onions
1/4 c. butter
1 c. catsup
1 c. pineapple preserves
2 tsp. dry mustard

Pack ham on a rack in a shallow baking pan. If desired, score top of ham in a diamond pattern. Making cuts about 1/4 inch deep. Insert a meat thermometer. Bake 1 1/4 to 2 1/2 hours in a 325 degree oven or until thermometer registers 140 degrees.

Meanwhile, for sauce: In a saucepan cook onions in butter until tender. Stir in catsup, preserves and dry mustard. Heat through. Brush some sauce onto ham before serving. Pass remaining sauce around.