Cauliflower Soup w/ Rice

This is creamy, comforting, and so satisfying! This recipe has saved me on my year-long elimination diet.
1 yellow sweet potato yielding 1 cup cooked
1 onion, chopped
2 cloves garlic, minced
2 stalks celery, diced
2 medium carrots, chopped
Florets from one medium head cauliflower
1 1/2 t marjoram
Salt to taste
Fresh ground pepper
Cooked brown rice or other grain*
Bake sweet potato in 350-degree oven until soft, about 2 hours. Higher temp is shorter time is needed.
Sauté onion in dry soup pot over medium-high heat until it starts to brown. Add garlic and sauté one more minute.
Add about 4 cups water and loosen browning off bottom of pan. Add celery, carrots, then lay cauliflower florets over the top so they can easily be scooped out. Bring to a boil then lower heat to medium, cover, and cook until cauliflower is tender.
Scoop out cooked cauliflower and place in a blender jar and blend until smooth. Add cooked sweet potato and blend. Stir in blender contents into soup pot along with marjoram and mix well. Heat for 5 minutes. Mix in cooked brown rice or other grain. Salt and pepper to taste.
*I love a combination of cooked quinoa and cook buckwheat. Boil 2 cups water, add 1 cup quinoa and ½ cup buckwheat. Lower heat to low, cover, and cook until tender, about 10 – 15 minutes.