Put the clams and water in a large saucepan and bring to the boil over a high heat. Reduce the heat, cover with a lid and cook for 5 minutes or until the clams open (discard any that remain stubbornly closed). Transfer the clams with a slotted spoon to a bowl. Strain the clam stock, adding water to make 350ml, if necessary; set aside. Wipe out the saucepan.
Lightly coat the saucepan with cooking spray and set over a medium heat. Add the bacon and onion, then sauté for 7 minutes or until the onion is golden. Sprinkle in the flour, then cook, stirring constantly, for 1 minute or until bubbling but not browned.
Add the potatoes, milk, reserved clam stock, thyme, bay leaf and cayenne pepper to the saucepan. Bring to a simmer and cook, stirring occasionally, for 10 minutes or until the potatoes are tender (do not allow to boil).
Meanwhile, remove the clams from their shells and cut into bite-sized pieces, if necessary. Stir the clams into the chowder and cook for a further 2 minutes or until heated through. Discard the bay leaf. Ladle into bowls, season with pepper and garnish with parsley.
Some more ideas…
MANHATTAN CLAM CHOWDER • Omit the milk and instead use 1 tin (400 g) no-salt-added chopped tomatoes and 1 cup (250 ml) salt-reduced chicken stock. • If fresh clams aren't available you can use 1 tin (about 200 g) of clams. Drain, rinse very well to remove the salty brine and drain again before use.
This lighter version of clam chowder is made with low-fat milk whisked with a little flour rather than with cream. This gives the chowder an authentic flavour without the fat.