Step 1

You can substitute an equal weight of penne, ziti, medium shells, farfalle, or orecchiette for the campanelle, if desired.

Step 2

Bring 4 quarts water to boil in Dutch oven. Add pasta and 1 tablespoon salt and cook, stirring often, until al dente. Reserve ½ cup cooking water, then drain pasta.

Step 3

Meanwhile, pat scallops dry with paper towels and sprinkle with salt and pepper. Heat 1 tablespoon butter in 12-inch nonstick skillet over medium-high heat until just smoking. Add half of scallops and cook, without moving them, until well browned, about 1½ minutes per side. Transfer to plate and tent with foil. Wipe out skillet with paper towels and repeat with 1 tablespoon butter and remaining scallops.

Step 4

Add 1 tablespoon butter to now-empty skillet. Stir in garlic and pepper flakes and cook until fragrant, about 30 seconds. Add clam juice and cook until reduced by half, about 2 minutes. Add pasta, reserved cooking water, Parmesan, parsley, lemon juice, and remaining 2 tablespoons butter and toss to combine. Serve pasta with scallops, passing extra Parmesan separately.