Fettuccine with Prosciutto and Peas

12 ounces fettuccine
1 T butter
1 large shallot, finely chopped (1/4 cup)
1/4 cup heavy cream
1 package frozen peas (10-ounces)
8 slices prosciutto (about 4 ounces), halved lengthwise and thinly sliced crosswise (about 1 cup)
1 T freshly grated lemon zest
1 T freshly squeezed lemon juice
1/2 cup finely grated parmesan cheese, plus more for the table

In a large pot of boiling salted water, cook the pasta until al dente. Reserve 1 cup of the pasta water; drain the pasta and return to the pot.

In a large skillet, melt the butter over medium-low heat; add the shallot and cook until softened (about 5 minutes). Add the cream, peas and prosciutto; bring to a gentle simmer over medium heat. Simmer until the peas are heated through, 3-4 minutes.

Stir in the lemon zest and juice. Pour the sauce over the pasta; add the parmesan, and season generously with salt and pepper. Add enough of the reserved pasta water to thin the sauce as desired. Serve immediately, top with additional parmesan.