Fettuccine with Scallops

Bring a large pot of water to a vigorous boil.
While the water comes to a boil, pat the scallops thoroughly dry with paper towels. If the scallops have a tough little rectangular portion on the side that's uncharacteristically dense and hard, trim and discard it.
Heat 1 tablespoon oil in a sauté pan over medium-high heat. Let the oil get very hot but not smoking. Add the scallops and sear on both sides, turning once, until almost cooked through. Remove the scallops from the skillet but keep the skillet on the stove.
Turn the heat beneath the skillet down to medium-low and add the remaining 2 tablespoons oil to the pan along with the minced shallots. Cook, stirring, until the shallots are softened and tender but do not let them brown, 2 to 4 minutes.
Add the cream and, stirring constantly, bring it to a gentle simmer. (If your pasta is still a while from being done, remove the skillet from the heat, cover to keep warm, and then return to a gentle simmer before proceeding.) Add the lemon zest, lemon juice, chervil, and, if you feel it's necessary, a very small ladleful of pasta water to the sauce and cook just until the sauce thickens, anywhere from 1 to 4 minutes.
Meanwhile, add the pasta and plenty of salt to the boiling water and cook until al dente.
Drain the pasta and return it to the pot. Add the cream sauce and scallops and toss gently to combine. Season with salt and pepper to taste and pile onto plates.