Instructions

Bring 2 quarts water to boil in large saucepan. Add 12 ounces rigatoni and 1½ teaspoons table salt and cook, stirring often, until al dente. Reserve 1½ cups cooking water, then drain pasta and return it to pot.
Meanwhile, melt 1 tablespoon unsalted butter in 12-inch skillet over medium-high heat. Add 1 pound chicken breasts, trimmed and sliced crosswise ¼ inch thick; ½ teaspoon salt; and ¼ teaspoon pepper and cook until chicken is golden brown and cooked through, 4 to 6 minutes. Transfer to bowl.
Reduce heat to medium; add 1 minced large shallot, 1 tablespoon minced garlic, ⅛ teaspoon red pepper flakes, and remaining ½ teaspoon salt and 3 tablespoons butter to now-empty skillet. Cook, stirring frequently, until shallot is softened, about 2 minutes. Stir in ¼ cup lemon juice, scraping up any browned bits. Stir in ½ cup chicken broth and bring to simmer. Reduce heat to medium-low and whisk in 4 ounces ⅓ less fat cream cheese (neufchatel), softened and cut into 12 pieces, until melted and smooth, about 1 minute. Off heat, stir in chicken and any accumulated juices.
Add chicken-sauce mixture, ¼ cup capers, ¼ cup minced parsley, and ½ cup reserved cooking water to pasta. Cook over low heat, stirring constantly, until pasta is coated in lightly thickened sauce, about 1 minute, adjusting consistency with remaining reserved cooking water as needed. Season with salt and pepper to taste. Transfer to platter. Garnish with extra parsley and serve, passing extra pepper separately.