How to Make It
Combine sour cream and peas in a small bowl.
Cook the pasta according to package directions. Drain, reserving 1/4 cup of the pasta water.
Return pasta to pot and fold in sour cream mixture, ham, 3/4 cup cheese, tarragon, salt, and pepper.
Divide among 4 bowls and garnish with additional tarragon and remaining Parmesan cheese.