Farfalle with Mascarpone, Roasted Asparagus, and Hazelnuts

2 pounds slender asparagus
3 tablespoons olive oil
Kosher salt and freshly ground black pepper
1 pound farfalle or bow tie pasta
One 8-ounce container mascarpone cheese
2/3 cup grated Parmesan cheese, preferably Parmigiano Reggiano, plus an optional extra chunk for shaving
1/2 cup toasted hazelnuts, coarsely chopped or crushed
3 tablespoons chopped chives

1.Arrange a rack at center position and preheat oven to 450 degrees F. Line a rimmed baking sheet with aluminum foil. Break off and discard the tough bases from the asparagus and then cut the spears on the diagonal into 2-inch lengths. Place sliced asparagus on the baking sheet. Drizzle them with oil, season with salt and pepper, and then toss well. Spread the sliced spears in a single layer. Roast until tender and lightly browned, about 10 minutes. Remove and set aside.          

2.Bring a large pot of water to a boil, then add pasta and 1 tablespoon salt. Cook until al dente, 10 to 12 minutes, or according to package directions. Remove and drain, reserving 1 cup of the pasta cooking water. Return pasta to pot in which it was cooked and stir in mascarpone, grated Parmesan cheese, and asparagus. Toss over low heat until pasta is coated with sauce and heated through, adding reserved pasta water by 1/4 cupfuls if dry, about 3 minutes. Taste and season with salt and pepper, if needed.           

3.Mound pasta in a large, shallow serving bowl.  Sprinkle with hazelnuts and chives. If desired, shave some thin slices from the chunk of Parmesan cheese over the pasta. Serve immediately. 

Serves 4 to 5 with large servings or 6 with smaller portions.