This is a most delicious soup that I came across in Vegetarian Times Magazine. I altered the original a bit and this is what I came up with. It was perfectly thick and smooth and yummy (and healthy!). Andrew loved it too.
2 tbsp. olive oil
1 large sweet onion, diced
3 tbs. tomato paste
3 tbsp. creamy peanut butter
1 shake cayenne pepper
a few shakes of cinnamon
2 cloves garlic, minced
3/4 tsp. cumin
2 medium sweet potatoes, peeled and sliced to 1/4 inch thick
3 1/2 cups vegetable broth
1 1/2 cups water
2 cups packed spinach leaves, thinly sliced
Heat oil in Dutch oven or large soup pot over medium high heat. Add onion and saute for 5 to 7 minutes. Stir in tomato paste, peanut butter, cayenne, garlic, cumin, cinnamon and cook for 1 minute, stirring constantly.
Add sweet potatoes, broth and water and simmer over medium-low heat, partially covered, 20 to 25 minutes or until potatoes are tender.
Blend mixture with an immersion blender or in food processor until rich and creamy. Bring soup back to simmer and stir in the spinach leaves.