Bring a large pot of water to a boil. Salt the water and add the pappardelle and peas. Cook until the pasta is tender, 2 to 3 minutes. (For dry pappardelle, cook according to the package directions, adding the peas during the last 2 minutes of cooking.)
Meanwhile, in a large bowl, mix the ricotta, Parm and zest; season with salt and pepper.
Drain the pasta, reserving 1/2 cup starchy cooking water. Add 1/4 cup cooking water to the cheese mixture and stir to form a thick sauce. Add the pasta, peas and half the basil to the sauce and toss to coat, adding more cooking water if too dry. Top with the remaining basil, and pass more Parmesan at the table.