Rinse the tomatoes and remove the stalks.
Make several incisions in the skin with a sharp knife.
Put in the microwave oven on a double layer of kitchen paper.
Cover and micro wave on HIGH for 2 minutes.
Skin the tomatoes, chop coarsely and put in the bowl of a food processor.
Add the celery and garlic and puree until smooth.
Pour the puree into a small casserole.
Add the thyme, bay-leaf, white wine, vinegar, sugar, Cayenne pepper and salt and pepper to taste.
Stir well.
Put in the microwave oven, uncovered, and cook on HIGH for 10 minutes, stirring midway through the cooking time.
Add the onions and golden raisins (sultanas) and pour over the olive oil.
Cover and microwave on HIGH for 10 minutes.
Prick the onions with a toothpick (cocktail stick) to test whether they are tender.
Actual cooking time will vary according to the size of the onions.
Leave to cool.
Discard the thyme and bayleaf and chill in the refrigerator for 2 hours