Here on the West Coast, razor clams and butter clams—large, meaty, and loaded with bivalve flavor—are the chowder clams of choice (though geoduck makes a good chowder, as does the horse clam).
But smaller hardshelled clams like the native littleneck and non-native manila can be used for chowder, too. The manila in particular is a bread-and-butter species around Puget Sound and can be easily collected on some beaches virtually every day of the year. Most of the time I steam my manilas and eat them out of the shell, as in Pasta alle Vongole, Black Bean Clams, Thai Red Curry Clams, Clams with Herbed Wine Sauce, and so on. Sometimes, though, the New Englander in me demands a chowder.
Fat of the Land. This was a recipe used mainly for flaky, white fish, notably cod, which we ate every summer at their home on Cape Cod. It uses salt pork, and it's relatively thin. I also understand the appeal of the sort of thick and creamy chowders that we've all had at clam shacks one time or another. The recipe below is one of those chowders, based on a recipe developed by the local Seattle fish 'n' chips house, Ivar's. It's a piscatarian chowder, which is to say it doesn't rely on bacon or salt pork. A couple limits of manilas will make this chowder.
1 cup white wine
3 - 4 cloves garlic, smashed
several sprigs parsley
1 1/2 cups clam meat
2 - 3 cups clam broth
2 cups peeled and diced potatoes
1 cup diced onion
1 cup diced celery
3/4 cup butter
3/4 cup flour
4 cups half and half, warmed
salt and pepper
dash red pepper flakes
1. Steam 80 manila clams in wine, garlic, and parsley. When clams have opened, strain broth through fine mesh sieve and save; you should have at least 2 cups. Remove meat from shells and roughly chop; you should have between 1 - 2 cups.
2. In a medium saucepan, simmer onions, celery, and potato in clam broth until potatoes are tender, about 20 minutes.
3. Meanwhile, in a heavy-bottomed pot, melt butter over medium heat. Slowly add flour, whisking, to make a roux. When roux is golden, slowly pour in warmed half and half while continuing to whisk. Add clam broth and vegetables and continue to stir. If chowder is still too thick, add more warm milk or half and half (or warm water, chicken stock, or clam juice).
4. Season with salt, black pepper, and red pepper. Garnish with oyster crackers. Wear your lobster bib.