Spaghetti allo scoglio

Method

1. Purge the clams. An hour in cold water salted to about 30 g per litre, which is roughly seawater. They spit out their sand. Skipping this is the single most common way this dish is ruined, because the grit ends up in the sauce and there is no removing it afterwards.
2. Open the clams and mussels separately. Wide pan, high heat, a splash of the wine, lid on. Shake once and pull them out into a bowl the moment they open, in batches if you have to. Strain the liquor through a fine sieve or a coffee filter and keep it. That liquor is the sauce. Discard anything still shut. Shell about two thirds and leave the rest in the shell for the plate.
3. Start the pasta. A large pot of water salted more lightly than usual, because the shellfish liquor is already salty. The spaghetti wants to reach the pan two minutes short of al dente. Save a mug of the water.
4. Sear the prawns and squid. Heat half the oil in a wide skillet until it shimmers. Prawns for about 1 minute a side, out. Squid in a single layer for no more than 2 minutes, out. Squid held between 3 and 25 minutes is rubber, and there is no rescuing it inside a pasta that cooks for eight.
5. Build the base. Rest of the oil on medium, the crushed garlic and chilli, 2 minutes until the garlic is pale gold and fragrant. Fish the garlic out. Add the tomatoes and cook 4 to 5 minutes until they slump and start to break.
6. Pour in the remaining wine, let it bubble hard for a minute to cook off the raw alcohol, then add the strained shellfish liquor and reduce until it is glossy and just coats a spoon.
7. Finish the pasta in the pan. Drag the spaghetti straight from the water into the sauce with a splash of the pasta water and toss over medium heat for 2 minutes, until it is al dente and the sauce is clinging rather than pooling. Keep tossing and keep adding water in small splashes: the starch and the oil emulsify only if they are agitated.
8. Return everything. Clams, mussels, prawns and squid back in, off the heat, with the parsley and lemon. Toss for 30 seconds to warm through and serve immediately, in wide bowls, with the shells on top.

Notes

• No cheese. This is not snobbery about a rule. Pecorino and parmesan are cured and salty and flatten the sweetness of shellfish, which is the entire point of the dish. If you want the creamy, cheesy version, that is a different recipe on this site and a good one.
• The liquor is the stock. Nothing else in this dish carries the sea flavour. Straining it matters as much as saving it, because the last of it holds whatever sand the purge missed.
• Timing is the whole recipe. Every element is cooked separately and returned at the end. It looks like more washing up and it is, but it is the difference between shellfish and erasers.
• Prawn heads. If your prawns have heads, squash them into the oil at step 5 and strain before the tomatoes go in. It is the cheapest depth you will ever add to a sauce.
• Leftovers. None worth having. The pasta drinks the sauce and the shellfish toughen.

Ingredient substitutions

• Clams. Vongole veraci are the traditional choice. In Germany, Venusmuscheln from a good fishmonger work; in Canada, littlenecks or Manila clams. If you can get none, double the mussels and add 100 ml of fish stock.
• Squid. Cuttlefish works and is sweeter. Frozen squid is genuinely fine here and is often more tender than fresh, because freezing breaks down the muscle.

Sources consulted

• Serious Eats: pasta allo scoglio
• BBC Good Food: how to cook mussels