To make the stock, remove any skin and fat from the chicken carcasses and legs, and put the carcasses in a large heavy-based saucepan with 3litres (12cups) cold water. Bring to the boil and skim any fat that floats to the surface. Add the remaining stock ingredients. Simmer for 1½ hours, skimming occasionally. Strain the stock (you should have about 1.5litres/6cups) and pour it back into the clean saucepan.
To make the clarification mixture, remove the skin and meat from the chicken drumsticks and discard the skin. Chop the meat finely (you will need about 150g/5½oz) and mix with the carrot, leek, celery, peppercorns, parsley, tomato and egg white. Add 200ml (7fl oz) of the warm stock to loosen the mixture.
Add the clarification mixture to the strained stock and whisk in well. Bring to a gentle simmer. As the mixture simmers the clarification ingredients will bind with any impurities and form a ‘raft’. As the raft rises, gently move it with a wooden spoon to one side of the pan away from the main movement of the simmering stock (this will make it easier to ladle out the stock later). Simmer for 1 hour, or until the stock is clear.
Ladle out the chicken stock, taking care not to disturb the raft, and strain through a fine sieve lined with damp muslin. Place sheets of paper towel over the top of the consommé and then quickly lift away to remove any remaining fat. Season with coarse sea salt (or other iodine-free salt, as iodine will cloud the soup).
Reheat before serving, season and garnish with parsley or cooked julienned carrot and leek.