I used to make chowder like this when I worked at the Point, a luxury resort in upstate New York. We served it in a large tureen on the terrace at lunchtime - the guests helped themselves and ate it while enjoying the view of the beautiful Adirondack mountains.
1.5kg fresh live clams (palourdes or amandes)
150g unsalted butter
40g plain white flour
200ml dry white wine
750ml hot fish stock
150g fresh sweetcorn kernels or drained and rinsed canned sweetcorn
1 Spanish onion, finely diced
1 leek (white part only) cut into 1cm dice
2 garlic cloves, finely chopped
1 large King Edward potato (about 200g), peeled and cut into 1cm dice
150ml double cream
A handful of fresh parsley (curly or flat-leaf), roughly chopped
Sea salt and freshly milled white pepper
Soak the clams in cold water for at least 20 minutes, or up to an hour, to clean them.
Meanwhile, make a beurre manié (butter and flour liaison). Soften 50g of the butter and mix in the flour to make a thick paste. Keep in the fridge until ready to use.
Drain the clams in a colander, rinse under the cold tap to check there's no sand left in the shells, and drain again. Discard any clams that are open or that do not close when tapped sharply on the worktop. Heat a wide pan over a high heat until hot, tip in the clams and wine, and cover the pan tightly. Give the pan a shake, then take off the lid - some or all of the clams will be open. Remove the open ones with a slotted spoon and set aside. Put the lid on again, and continue until all the clams have opened. (Discard any that stay closed.)
When the clams are cool enough to handle, remove most of them from their shells, reserving some in shells for the garnish. Pour the cooking liquid slowly through a fine sieve into a clean pan, leaving the sediment behind in the bottom of the first pan. Mix the hot fish stock with the cooking liquid and set aside.
If using fresh sweetcorn, blanch it in a small pan of salted boiling water for one minute, then drain and rinse under the cold tap.
Heat the remaining butter in a heavy pan over a medium heat. Add the onion, leek, and garlic, and cook without colouring for a few minutes until they start to soften. Season with a little salt. Add the potato and cook for about five minutes until softened, then remove from the heat and stir in the shelled clams and sweetcorn. Set aside.
Bring the fish stock to the boil. Whisk in the beurre manié in small pieces, then boil and whisk until thickened. Stir in the cream and bring back to the boil, then add the clams and vegetables and heat through gently for a minute or two. Season lightly, and finish by adding the clams in their shells and the parsley. Serve hot.
Key to perfection: The liquid in a chowder should be like velvet, and there are two ways to achieve this. You should remove all the sand and grit from the clams before you start cooking, then use a beurre manié at the end to thicken the liquid and give it a smooth consistency. Classic recipes thicken the chowder once everything is in, but it's better to thicken the stock on its own so you don't crush the delicate potatoes and clams.
By Marcus Wareing