Peel and quarter the pineapple and remove the hard stalk. Finely dice the flesh. Peel onions and also dice finely. Sauté both in hot olive oil. Add mustard seeds, green pepper, vinegar and sugar.
Bring to the boil while stirring. Then let it boil down a little bit in an open pot for about 20 minutes. Rub spare ribs with oil, salt and pepper and grill on the hot grill for about 15 minutes, turning occasionally.
Serve with the cooled chutney.