Step 1: Preheat and Prepare the Vegetables : Preheat your oven to 200°C (400°F). On a baking sheet, spread the chopped carrots, fennel, onion, and garlic. Drizzle with olive oil and season generously with salt, pepper, thyme, and rosemary. Toss to coat evenly.
Step 2: Roast Until Tender and Golden : Roast the vegetables for 25–30 minutes, flipping halfway through, until carrots are tender and slightly caramelized at the edges. This roasting step builds deep, rich flavors and enhances natural sweetness.
Step 3: Blend the Soup Base : Transfer the roasted vegetables into a large pot or blender. Add about 3 cups of warm broth. Blend until smooth and creamy. (If using a regular blender, work in batches and be cautious with hot liquids.)
Step 4: Adjust and Simmer : Pour the blended soup back into the pot. Add the remaining broth to adjust consistency. Bring to a gentle simmer over medium heat for about 5–7 minutes. Stir in butter (or olive oil) and cream (if using). Taste and adjust seasoning with salt and pepper.
Step 5: Finish and Garnish : Ladle into bowls and garnish with chopped parsley or dill. Add a drizzle of cream or olive oil for a restaurant-style finish.