25g (1 oz) butter
30ml (2 tbsp) olive oil
1 medium onion, skinned and chopped
1 leek, trimmed and sliced
1 small bulb fennel, sliced
1 celery stick, sliced
1 garlic clove, crushed
15ml (1 tbsp) chopped fresh thyme
2 large tomatoes, skinned and sliced
300ml (1/2 pint) dry white wine
300ml (1/2 pint) fish stock
900g (2 lb) mussels
4 fillets of sole
salt and freshly milled black pepper
a pinch of cayenne
2.5ml (1/2 tsp) powdered saffron
60ml (4 tbsp) double cream |