In a large pot, heat the olive oil over medium heat.
Add the chopped onion and cook until it becomes translucent, about 5 minutes.
Stir in the minced garlic and cook for another minute.
Add the chopped carrots and cauliflower florets to the pot, stirring to combine with the onion and garlic.
Pour in the vegetable broth and water, then add the dried thyme.
Bring the mixture to a boil, then reduce the heat and let it simmer for about 20-25 minutes, or until the vegetables are tender.
Use an immersion blender to blend the soup until smooth. Alternatively, carefully transfer the soup in batches to a blender and blend until smooth.
Season with salt and pepper to taste.
Serve hot, garnished with fresh parsley and/or black pepper, if desired.