In a large pot, heat olive oil over medium heat. Add chopped onion and sauté for 3-4 minutes until soft.
Add garlic and cook for another minute until fragrant.
Stir in the chopped carrots and cauliflower florets. Cook for 5 minutes, stirring occasionally.
Pour in the vegetable broth and bring to a boil. Reduce heat and simmer for 20-25 minutes, or until vegetables are tender.
Using an immersion blender, puree the soup until smooth and creamy. Season with salt and pepper to taste.
Ladle into bowls, garnish with fresh parsley if desired, and serve warm.