Pesto Orecchiette with Sausage

12 ounces orecchiette pasta (I usually use shell pasta as a substitute)
1/2 pound green beans, trimmed and cut into 1-inch pieces
1 cup frozen peas
1 tablespoon olive oil
8 ounces fully cooked Italian-style chicken sausage links, thinly sliced (I use 4 links)
1/3 cup pesto
1/2 cup grated Parmesan (2 ounces)

1 Cook the pasta according to the package directions, adding the green beans and peas during the last 3 minutes of cooking. Reserve 1 cup of the cooking water; drain the pasta and vegetables and return them to the pot.
2 Meanwhile, heat the oil in a large skillet over medium-high heat. Add the sausage and cook, turning occasionally, until browned, 6 to 8 minutes.
3 Add the sausage, pesto, Parmesan, and 1/2 cup of the reserved cooking water to the pasta and vegetables and toss to combine (add more cooking water if the pasta seems dry).