Preparation

1. Preheat oven to 450°F. Line a baking sheet with aluminum foil and lightly coat with cooking spray.
2. Evenly spread out broccoli and cauliflower florets over baking sheet and drizzle with 2 tablespoons olive oil, 2 teaspoons kosher salt, and 1 teaspoon black pepper. Roast for 20-25 minutes or until both are tender and edges are crisped. Remove from oven and set aside.
3. In a large pot or Dutch oven, sauté onions in 1 tablespoon olive oil. Season with ½ teaspoon salt and ⅛ teaspoon black pepper. Add minced garlic and cook until fragrant, about 1 minute.
4. Add 4 cups of broth to the pot along with the broccoli and cauliflower. Cover and simmer for 15 to 20 minutes.
5. Prepare a roux, whisking butter and flour in a medium-sized pan until flour has melted into butter. Slowly add heavy cream, whisking constantly until flour is cooked through, about 5 minutes. Remove from heat and set aside.
6. Use an immersion blender to puree vegetables and broth until smooth. If using a standard blender, transfer broth and vegetables in small batches and puree, then return to stock pot.
7. Once all of the vegetables have been pureed, add roux to the pot and stir to incorporate.
8. Add white cheddar cheese and stir until melted. Add more broth, if needed, until soup reaches desired consistency.
9. Add more salt and pepper, to taste, before serving. Optional: garnish with sprigs of broccoli floret and cheddar cheese.