Cheesy Potato-Cauliflower Soup

1 . Stage

Combine cauliflower, potatoes, broth, celery, carrots, and onions in a large saucepan; bring to a boil. Cover and cook until vegetables have softened, about 10 minutes. Remove from the heat but keep the lid on.

2 . Stage

Melt butter in another large saucepan over medium heat. Whisk in flour; cook and whisk until bubbly and brown, about 3 minutes. Remove from heat and gradually whisk in milk. Return to medium heat and cook until thickened, 5 to 10 minutes.

3 . Stage

Add veggies and broth to the milk mixture. Continue stirring. Add vinegar, garlic powder, lemon juice, cayenne, salt, and pepper. Remove from the heat and slowly add Cheddar, Swiss, and American cheeses, stirring well until melted.

4 . Stage

Ladle into bowls and garnish with scallions.