In a 3-quart saucepan, melt butter over medium-high heat until foaming. Add broccoli, onion, and celery. Sauté until softened, about 10 minutes.
Stir in flour and cook until lightly browned, about 1 minute. Whisk in 2 1/2 cups broth and bring to simmer.
Simmer until veggies are tender, about 10 to 12 minutes longer. Transfer to blender and puree until smooth.
Wipe out saucepan. Return pureed soup to pan. Add remaining 1 1/2 cups chicken broth and cream. Bring to simmer and stir until heated through. Season to taste with salt and white pepper. Garnish with croutons if desired.
Broccoli: You'll need 4 cups of chopped broccoli, or about 24 ounces. Feel free to use all florets or a mix of stems and florets; root to stem cooking at its best!
Chicken broth: Store-bought or homemade Chicken Broth; either work great. For a vegetarian Cream of Broccoli Soup, substitute with vegetable broth.
Croutons: Since this soup is delightfully smooth, I like to garnish each bowl with a small handful of crunchy croutons for contrast. Buy them at the supermarket, or to make homemade croutons, slice or tear 1 loaf of bread into 1/2-inch pieces. Preheat the oven to 450 degrees. In a small bowl, whisk together 1/4 cup olive oil, 1 teaspoon garlic powder, 1 teaspoon Italian seasoning, and 1/4 teaspoon salt. In a large bowl, add the bread pieces and the olive oil mixture, then toss to combine. Spread the croutons on a parchment paper-lined rimmed baking sheet. Bake until golden brown, or for about 10 to 15 minutes.
Yield:This recipe makes eight 1-cup servings, ideal for a lunch main dish or a dinner appetizer.
Storage:Store leftovers covered in the refrigerator for up to 4 days.
Make ahead:The soup can be made up to 3 days in advance and reheated on the stove. Garnish with croutons just before serving.
Freezer:Cream of broccoli soup is great for the freezer! Cool soup completely, then divide into freezer-safe containers (I love pint-sized glass mason jars). Leave 1/2-inch head space for expansion, then date, label, and freeze for up to 3 months. Thaw overnight in the refrigerator.
More garnish ideas: Instead of, or in addition to the croutons, get creative with your toppings. Try crumbled crispy bacon, cubes of a grilled cheese sandwich, or a dollop of sour cream or plain Greek yogurt. Blanched broccoli florets are always nice, too.