In a large pot over medium heat, melt 1 tablespoon of butter.
Add 1 clove of crushed garlic and cook for 30 seconds.
Stir in 1/4 teaspoon ground nutmeg, 1/4 teaspoon ground black pepper, and 1 1/2 teaspoons salt. Cook for another 30 seconds.
Pour in 6 cups of water and add the chopped head of cauliflower.
Bring the mixture to a boil, then reduce heat, cover, and simmer for 20 minutes until the cauliflower is tender.
In a separate small saucepan over medium heat, cook the cubed large carrot with enough water to cover until just tender. Drain and reserve.
Puree the cauliflower soup using a blender, food processor, or immersion blender.
Stir in the reserved carrots, 1/3 cup chopped green onion, and 1/4 cup chopped parsley.
Serve the smooth cauliflower soup.