1 pound gnocchi-shaped pasta (such as cavatelli) or shell pasta
3 tablespoons olive oil
1 large red onion, halved, sliced crosswise
4 skinless boneless chicken breast halves, cut crosswise into 1/3- to 1/2-inch-thick slices
4 teaspoons chopped fresh rosemary
1 head of curly endive, trimmed, very coarsely chopped (about 12 cups)
1 1/2 cups crumbled blue cheese (such as Maytag; about 9 ounces)
3/4 cup coarsely chopped toasted walnuts (optional)
Directions
Cook pasta in large pot of boiling salted water until just tender but still firm to bite, stirring occasionally.
Meanwhile, heat oil in heavy large deep skillet over medium-high heat. Add onion; sauté until slightly softened, about 4 minutes. Sprinkle chicken with salt and pepper; add to skillet with rosemary and sauté until chicken is almost cooked through, about 4 minutes. Add endive; toss until slightly wilted and chicken is cooked through, about 1 minute.
Drain pasta, reserving 3/4 cup pasta cooking liquid. Return pasta to pot. Add chicken mixture, blue cheese, and enough pasta cooking liquid to moisten; toss to blend. Season with salt and pepper. Transfer to large bowl; sprinkle with nuts, if desired.
