Poulet à la Marengo from The Robert Carrier Cookbook by Robert Carrier

Ingredients

• 1 tender chicken
• 12 button mushrooms, sliced
• 2 tablespoons butter
• salt and freshly ground black pepper
• bouquet garni (4 sprigs parsley, 1 stalk celery, 1 bay leaf)
• well-flavoured chicken stock
• lemon juice
• cayenne pepper
• croûtons of fried bread or crescents of flaky pastry
• 2 shallots, finely chopped
• 2 tablespoons olive oil
• 1 tablespoon flour
• 4 tablespoons tomato concentrate
• 1 glass dry sherry