Making Roasted Celery and Potato Soup is straightforward if you follow these simple steps:

1. Preheat Oven: Begin by preheating your oven to 400°F (200°C).
2. Prepare Vegetables: Chop the celery, potatoes, and onion into even-sized pieces. Mince the garlic.
3. Toss with Oil: Spread the chopped vegetables onto a baking sheet. Drizzle with olive oil, salt, pepper, and thyme. Toss to coat evenly.
4. Roast: Place the baking sheet in the preheated oven and roast for 25-30 minutes, or until the vegetables are tender and slightly caramelized.
5. Blend: Once roasted, transfer the vegetables to a large pot. Add the vegetable broth and bring to a simmer over medium heat.
6. Add Cream (if desired): Stir in the heavy cream for added richness and blend the mixture with an immersion blender until smooth. If you don’t have an immersion blender, you can transfer the mixture to a regular blender in batches.
7. Season to Taste: Taste the soup and adjust the seasoning with additional salt and pepper, if needed.
8. Serve: Ladle the soup into bowls and garnish with fresh parsley if desired.

These steps will lead you to create the most incredible Roasted Celery and Potato Soup with minimal fuss!