3. Step
Reduce heat to low and whisk in pumpkin, broth, half and half, vinegar, pepper, salt and 4 tablespoons Parmesan; cook, stirring constantly, until reduced and thickened, about 3 minutes. Stir in the pasta and enough of the reserved cooking water to achieve desired consistency. Divide among 4 bowls and top each with 1 tablespoon Parmesan.