Step 1

Place 1 1/2 pounds clams and 1 pound mussels in a large bowl of cold, lightly salted water and let soak for 10 minutes. Drain well. Scrub the shells gently and debeard the mussels if needed (here’s a tutorial).

Step 2

Bring a large, heavy-bottomed pot or Dutch oven of heavily salted water to a boil. Meanwhile, Thinly slice 1 large shallot (about 1/2 cup). Mince 4 large garlic cloves (about 1 tablespoon). Finely grate the zest from 1 medium lemon, then juice the lemon (3 to 4 tablespoons). Cut the second lemon into wedges for serving. Finely chop 1/4 cup fresh parsley leaves.

Step 3

When the water is boiling, add 1 pound dried pasta and cook until 2 minutes less than al dente, about 8 minutes or according to the package instructions. Reserve 1 cup pasta cooking water. Drain the pasta.

Step 4

Dry the same pot, then add 3 tablespoons olive oil and heat over medium-high heat until shimmering. Add the shallots and cook until softened, 2 to 3 minutes. Add the garlic, 1/2 teaspoon red pepper flakes, and 1/4 teaspoon kosher salt, and cook until fragrant, about 1 minute. Add 3/4 cup dry white wine and bring to a boil.

Step 5

Add the mussels and clams. Cover and cook, shaking the pan occasionally, until the clams and mussels open, 5 to 7 minutes. As the mussels and clams open, use tongs to transfer them into a large bowl. Discard any that do not open. Vigorously simmer until the liquid in the pot is reduced by half, about 3 minutes. Meanwhile, cut 3 tablespoons unsalted butter into 3 pieces.

Step 6

Add the pasta, butter, and 1/4 cup of the pasta cooking water to the pot. Toss until the pasta is al dente, adding more pasta water a tablespoon at a time (you may not need it all), until the sauce is thickened and coats the pasta, about 2 minutes. Add the reserved lemon zest, lemon juice, parsley, and a few grinds of black pepper, and gently toss until combined. Taste and season with more kosher salt and black pepper as needed.

Step 7

Remove from the heat. Add the mussels and clams and any accumulated juices and toss to combine. Transfer to bowls, dividing the mussels and clams evenly among each. Garnish with more red pepper flakes if desired and serve with the reserved lemon wedges.