Clams, potatoes and green sauce

Simplicity is beauty. I've had more pleasure from a ripe and juicy nectarine than I have from a complicated fondant.According to William Morris, things should either be useful or beautiful, and if you mix that with the idea that less is more and apply it to food, you should be OK. It's something the Italians know well with their cooking; start with good ingredients and you're pretty much all the way there. And, the Spanish as well, which is where the idea for this dish came from.Today's recipe is elegant and parsimonious in its ingredients, it uses clams which are at their best at this time of year from the cold waters around the UK. It's much more than the sum of its parts. I've used Cornish ones but this dish would be equally delicious with what the Scottish call 'spoots'. I'd call it Occam's razor clams.Ingredients12 baby potatoes, halved1 small white onionA bunch of parsley200ml garlic oil (made by grating four cloves of garlic into 500ml olive oil and heating until golden. Leave to cool then strain and keep in the fridge for up to a week)1tbsp flourA bag of clamsSherry vinegar to tasteWater for the sauceSalt and pepper to seasonMethodSoak the clams in cold water for about 20 minutes in a few changes of water then give them all a good slosh about until all the grit and sand has been cleaned away.Make the green sauce by blitzing together the parsley, a good load of garlic oil and a generous splash of sherry vinegar. Season well, taste and perhaps season a little more, not forgetting that vinegar is a seasoning and brings out flavours too, so adjust as you like. You may want it sharper, saltier or sweeter with more oil.Cook the potatoes in salted, boiling water until tender. About ten minutes. Drain them and run them under cold water to stop them cooking any more.Heat the garlic oil in a large, heavy saucepan, something like a le Creuset casserole.Finely chop the onion and gently sauté in the oil, well seasoned with salt, until soft and just starting to think about turning golden.Add the potatoes and cook them for a few minutes until they start to catch here and there and colour a little.Stir in the flour and add a splash of sherry vinegar then stir in a good splash of water until you have a thick sauce the consistency of double cream.Add the clams and cook with the lid on for about five minutes, until they've all opened. Or at least until all the ones that are going to open, open. Throw the others away.Add the green sauce to the pan, stir well, warm through and serve with some more chopped parsley and a little bread to mop up the incredible juices.