Two Peas In A Pasta

8 green onions-finely chopped
2 tablespoons unsalted butter
1 cup low-sodium chicken broth
1 cup heavy cream
3/4 cup water
2 cups shelled fresh peas (2 to 2 1/2 pounds in pods)
1/2 pound snow peas, trimmed and halved lengthwise (3 1/2 cups)
1 1/2 t kosher salt
1/2 t black pepper
1 pound dried egg fettuccine nests
1/3 cup chopped fresh flat-leaf parsley
2 t finely grated fresh lemon zest
1/3 cup finely grated parmesan plus additional for serving

Cook green onions in butter in a 12-inch heavy skillet over moderately low heat, stirring, until tender, about 5 minutes.
Add broth, cream, and water and simmer, uncovered, about 5 minutes.
Stir shelled peas into sauce and simmer 3 minutes.
Stir in snow peas, salt, and pepper and simmer until peas are tender, about 5 minutes.
Cook pasta in a 6- to 8-quart pot of boiling salted water. Drain pasta, then add to sauce, tossing to combine.
Sprinkle parsley, zest, and parmesan on top and toss again. Season with pepper.