- 3 cups chicken broth
- 1 (10 ounce) package frozen corn kernels
- 1 (10 ounce) package frozen petit green peas
- 1 (10 ounce) package frozen green beans
- 4 tablespoons butter, divided
- 1 large onion, cut into medium dice
- 1 large carrot, cut into medium dice
- 2 teaspoons celery seed
- 1/3 cup all-purpose flour
- 1 1/2 cups milk
- 2 cups shredded sharp Cheddar cheese
- Salt and ground black pepper to taste
- Heat broth and frozen vegetables in a large plate-covered microwave-safe bowl until hot, about 15 minutes.
- Meanwhile, heat 1 tablespoon of butter in a large soup kettle or Dutch oven over medium-high heat. Add onions and carrots; saute until tender, about 5 minutes. Add celery seed and saute to bring out flavor, about 1 minute. Add hot broth and vegetable mixture and bring to a boil. Reduce heat, cover and simmer until vegetables are tender, 7 to 8 minutes.
- While soup simmers, melt remaining butter in a medium saucepan over medium heat. Whisk in flour until smooth and cook, 1 minute. Slowly whisk in milk, and cook, stirring constantly, until mixture is thick and bubbly. Add cheese; whisk until melted, 1 to 2 minutes. Stir cheese sauce into soup and heat through. Season with salt and pepper and serve.