In a Dutch oven, cook sausage, mushrooms and onion over medium-high heat until sausage is no longer pink and vegetables are tender, 8-10 minutes, breaking up sausage into crumbles; drain. Add garlic; cook 1 minute longer. Add stock, pumpkin, sugar and seasonings. Bring to a boil; reduce heat. Cover and simmer 10 minutes.
Stir in cream. In a small bowl, mix water and cornstarch until smooth. Stir into pan. Bring to a boil; cook and stir until thickened, 1-2 minutes. Add cheese; cook and stir until melted.
Health tip: Use Italian turkey sausage, half-and-half cream and just one cup of cheese to save about 8g saturated fat. Test Kitchen tips
If you're lucky enough to have leftovers, try some spooned over biscuits.
Don't be tempted to substitute plainer cheese for the smoked cheddar. The smoky cheese really adds a complementary flavor to the soup.