Melt 1 tablespoon butter in a skillet over medium-high heat. Saute onion in hot butter until translucent, about 5 minutes. Set aside.
Whisk ¼ cup melted butter and flour together in a large saucepan over medium-low heat; cook until flour loses its granular texture, adding 1 to 2 tablespoons of milk if necessary to keep the flour from burning, 3 to 4 minutes.
Gradually pour milk into flour mixture while whisking constantly. Stir chicken stock into milk mixture. Bring to a shimmer; cook until flour taste is gone and mixture is thickened, about 20 minutes. Add broccoli, carrots, sauteed onion, and celery; simmer until vegetables are tender, about 20 minutes.
Stir Cheddar cheese into vegetable mixture until cheese melts. Season with salt and pepper to taste.
Tip: Aluminum foil helps keep food moist, ensures it cooks evenly, keeps leftovers fresh, and makes clean-up easy.
– 1 tablespoon butter
– ½ onion, chopped
– ¼ cup melted butter
– ¼ cup flour
– 2 cups milk
– 2 cups chicken stock
– 1 ½ cups coarsely chopped broccoli florets
– 1 cup matchstick-cut carrots
– 1 stalk celery, thinly sliced
– 2 ½ cups shredded sharp Cheddar cheese
– Salt and ground black pepper to taste