Whisk oil, lemon zest and juice, garlic, and ¼ teaspoon salt together in bowl, then stir in Parmesan until thick and creamy.
Meanwhile, bring 4 quarts water to boil in large pot.
Add shrimp and 1 tablespoon salt and cook until opaque throughout, about 1 minute.
Using slotted spoon, transfer shrimp to bowl, season with salt and pepper to taste, and cover to keep warm.
Return pot of water to boil.
Add pasta and cook, stirring often, until al dente.
Reserve ½ cup cooking water, then drain pasta and return it to pot.
Add oil-garlic mixture, cooked shrimp, basil, and butter and toss to combine.
Season with salt and pepper to taste, and adjust consistency with reserved cooking water as needed.
Serve.
Credit: The Complete Cooking for Two Cookbook (The Complete ATK Cookbook Series) (p. 228). America's Test Kitchen. Kindle Edition.