Cook’s tip: Sherry vinegar is matured in wooden barrels by methods similar to those used for sherry itself. It has a rich, mellowflavour that makes it popular in cooking. If sherry vinegar is unavailable, you can use red wine vinegar instead.
Variation: For a vegetarian soup, use a good vegetable stock instead of beef stock and stir in 1⁄2 teaspoon yeast extract for a richer flavour and colour. For the croûtes, use a Swiss-style non-animal rennet cheese as Gruyère is not suitable for strict vegetarians.
Each serving: 17 g protein, 23 g fat of which 7 g saturates, 29.5 g carbohydrate, 7 g fibre, 408 Calories