Ingredients

For the shrimp and pasta:

• 12 ounces dried fettuccine pasta
• 1 pound (17 to 21 per pound) peeled and devined raw shrimp, thawed if frozen
• 1/2 teaspoon kosher salt
• 1/4 teaspoon freshly ground black pepper
• 1 tablespoon unsalted butter

For the sauce:

• 4 tablespoons (1/2 stick) unsalted butter
• 2 cloves garlic, minced
• 1 1/2 cups heavy cream or half-and-half
• 2 1/2 ounces Parmesan cheese (2/3 cup finely grated or heaping 3/4 cup store-bought grated)
• 1/2 teaspoon kosher salt
• 1/4 teaspoon freshly grated nutmeg
• 1/4 teaspoon freshly ground black pepper
• Chopped fresh Italian parsley leaves, for serving

1. Bring a large pot of salted water to a boil. Add 12 ounces dried fettuccine pasta and cook until al dente, about 12 minutes. Reserve 1/2 cup of the pasta cooking water, then drain the pasta, but do not rinse.
2. Pat 1 pound (17 to 21 per pound) peeled and devined raw shrimp dry with paper towels and season with 1/2 teaspoon kosher salt and 1/4 teaspoon freshly ground black pepper. Melt 1 tablespoon unsalted butter in a large skillet over medium-high heat, then swirl the pan to coat the bottom with the butter. Add the shrimp in an even layer and cook, until pink and opaque throughout, 1 to 2 minutes per side. Transfer the shrimp to a plate, but do not clean the skillet.
3. Melt the 4 tablespoons unsalted butter in the skillet over medium heat. Add 2 minced garlic cloves and cook until fragrant, 30 seconds to 1 minute. Whisk in 1 1/2 cups heavy cream until combined and simmering, 3 to 4 minutes. Whisk in 2 1/2 ounces grated Parmesan cheese, 1/2 teaspoon kosher salt, 1/4 teaspoon freshly grated nutmeg, 1/4 teaspoon freshly ground black pepper, and 2 tablespoons of the reserved pasta water. Cook, whisking occasionally, until the sauce thickens to coat the back of a spoon, 3 to 4 minutes.
4. Add the drained pasta to the sauce and toss to coat. Return the shrimp to the pan and toss to combine. Serve garnished with chopped fresh parsley.