12 oz. fettuccine (preferably fresh, but can use dried)
2 Tbsp. (1/4 stick) unsalted butter
4 oz. thinly sliced prosciutto, torn into 1" pieces
Zest and juice of 1 orange
1/2 cup heavy whipping cream
Freshly ground black pepper
1/4 cup finely grated Parmesan
Bring a large pot of water to a boil. Season with salt; add pasta and cook according to package directions. Drain, reserving 1/4 cup pasta water.
Meanwhile, melt butter in a large heavy nonstick skillet over medium-high heat. Add prosciutto; sauté until browned, about 3 minutes.
Add reserved pasta water, orange juice, half of zest, and cream; bring to a boil. Add pasta; cook, stirring, until sauce coats pasta and pasta is al dente, about 1 minute. Season with salt and pepper. Stir in cheese and divide among warm bowls. Sprinkle remaining orange zest over pasta.