Sweet Sour Baby Onions

14 oz (400 g) baby onions, peeled 2 small pieces of orange rind 14 fl oz (400 ml) red wine vinegar 8 tbsp cane sugar (white, demerara or soft light brown) salt Place half the onions in a single layer in a wide, fairly shallow flameproof casserole dish, half in another, similar casserole dish. Sprinkle [...]