Heat olive oil in a large pot over medium heat. Add diced onion and sauté until translucent, about 5 minutes. Stir in minced garlic and cook for an additional minute.
Add Root Vegetables
Incorporate chopped carrots, parsnips, sweet potato, and celery root into the pot. Sauté for 5 minutes to enhance their flavors.
Simmer The Soup
Pour in vegetable broth and water. Add thyme, rosemary, bay leaf, salt, and pepper. Bring to a boil, then reduce heat to low, cover, and simmer for 30 minutes until vegetables are tender.
Blend To Perfection
Remove the bay leaf. Use an immersion blender to puree the soup until smooth. Alternatively, blend in batches using a countertop blender, then return to the pot.
Add Creaminess
Stir in heavy cream or coconut cream for added richness, if desired. Adjust seasoning with additional salt and pepper as needed.
Serve And Garnish
Ladle the soup into bowls and garnish with chopped fresh parsley. Serve warm.
Notes
This soup is versatile and forgiving. Feel free to adjust the types and quantities of root vegetables based on what's available or in season. The key is to maintain a balance of flavors and textures to achieve that creamy, comforting consistency.