It was only after I’d committed to enough seafood to feed ten that I thought to ask the fishmonger’s wife what to do with it. I’d gone to my usual fish stand in my Paris neighborhood and said that I had pasta for a crowd in mind. I was thinking about something based on butter, white wine, and herbs, but Madame suggested I start with slow-cooked squid in tomato sauce and that I shouldn’t forget a little hot pepper at the end. “It’s what we do in Portugal,” she said. And it’s what I did and continues to do, although the fish changes according to what I can get. These days I’m likely to cook squid rings (most often bought frozen and sliced when they’re still a little icy) and then add chunks of a firm fish, like monkfish, swordfish or tuna, and shrimp.

It’ll take an hour or so to simmer the sauce — you’ll want to go slow for the sake of the squid — but it bubbles away merrily without your having to do much. You can also do this part ahead, making it a dish that’s good for parties, which is how it all started.

For the clam juice, look for a brand that includes only clam juice and salt. Finally, choose your crushed tomatoes carefully—I like San Marzano tomatoes here.

Ingredients:

2 tablespoons olive oil
1 large onion, finely chopped, rinsed, and patted dry
2 garlic cloves, germ removed and finely chopped
Fine sea salt
¼ cup (60 ml) white wine or dry vermouth
1 pound (454 grams) cleaned squid, cut into 1/4-to-1/2-inch-thick rings, and patted dry
One 14 1/2-ounce (411-gram) can crushed tomatoes, such as San Marzano
1 sprig of fresh rosemary
1 sprig of fresh thyme
1 cup (240 ml) clam juice (see headnote)
¾ pound (340 grams) long pasta, such as spaghetti or fettuccini
3/4 pound (340 grams) firm fish fillets (see headnote), cut into bite-sized pieces
12 to 16 large shrimp (more if they’re small), peeled and deveined
Crushed red pepper flakes
2 tablespoons tomato paste
1 to 2 tablespoons cold unsalted butter
Grated zest and juice of 1 lemon (optional)
Chopped fresh herbs, such as parsley, chives, and/or tarragon, for serving (optional)

WORKING AHEAD
You can get the squid and sauce done a couple of hours or up to a day ahead; refrigerate it if you’re keeping it for more than 2 hours.

Instructions:

Warm the oil in a large skillet or deep saute pan over medium-low heat. Add the onion and garlic, season lightly with salt, and cook, stirring, until the onion is soft, about 5 minutes. Turn the heat up a little and pour in the wine. Cook, stirring until it almost evaporates, and then stir in the squid. Reduce the heat to low, season the squid lightly with salt, and cook, stirring often, for 5 minutes. Add the tomatoes, herb sprigs, and clam juice, and increase the heat just enough to bring the mixture to a simmer. Cover the skillet (use a baking sheet if you don’t have a lid), turn the heat down low, and let the squid cook, stirring only occasionally, for 30 minutes, until it is tender.

Remove the lid and simmer for another 20 minutes or so, again stirring now and then, until the sauce has reduced by about one-third. Remove the herb sprigs. (You can cover the pan and set the sauce aside for up to 2 hours, or refrigerate it overnight; bring to a simmer before continuing.)

Bring a large pot of generously salted water to a boil. At this point, everything comes together quickly, so be prepared to have the dish on the table in less than 15 minutes. Make sure the sauce is at a simmer and, if you chilled it, that the squid is hot.

Add the pasta to the boiling water and set the timer for al dente.

Drop the fish pieces into the sauce. Then, 4 minutes before the timer is set to ring, add the shrimp and some pepper flakes — go easy, you can add more at the table. Scoop out 1 tablespoon of the pasta water, mix it together with the tomato paste and blend it into the sauce.

When the pasta is cooked, drain it, shaking off as much water as you can. Turn the pasta out into the skillet (if your skillet isn’t large enough, turn the pasta out into a large bowl and stir the sauce into it) and stir to coat all the strands. Taste for salt and pepper flakes and add the butter and the lemon zest and juice, if you want some tang. Scatter over the chopped herbs, if using, and serve immediately.