Step 1

Bring 4 quarts water to boil in large pot. Add pasta and 1 tablespoon salt and cook, stirring often, until al dente. Reserve 1/2 cup cooking water, then drain pasta and return it to pot.

Step 2

Meanwhile, cook sausage in 12-inch nonstick skillet over medium heat, breaking up pieces with spoon, until cooked through, about 8 minutes. Using slotted spoon, transfer sausage to paper towel–lined plate. Add shallots to fat left in pan and cook over medium-high heat until softened, about 3 minutes. Add the garlic (if using) and cook for 1 minute, or until fragrant.

Step 3

Add wine and simmer until almost evaporated, about 2 minutes. Add cream and broth and simmer until sauce is slightly thickened, about 7 minutes. Stir in sausage and cook to let flavors meld, about 2 minutes. Remove from heat, stir in Parmesan, and season with salt and pepper to taste. Add sauce and chives to pasta and toss to combine. Adjust consistency with reserved cooking water as needed. Serve with extra Parmesan.