Creamy Carrot and Sweet Potato Soup

I've made different renditions of carrot soup in the past, but this is my favorite. There aren't a lot of flavors vying for attention in your mouth, just the sweetness of carrots with a hint of sweet potatoes. I use the word "hint" because I was able to slip the dreaded sweet potato into this soup without my husband complaining ... until he requested the ingredient list. He still ate the soup after he knew the ingredients, so it passed his palate test.

Update in 2015: My husband said I must have made this when I was starving him. It now ranks in the category of "You don't need to make this again."

Creamy Carrot and Sweet Potato Soup
3 Tbsp. butter, divided
1 cup chopped onion
1/4 tsp. cinnamon
1/4 tsp. nutmeg
4 3/4 cups cubed, peeled sweet potatoes
3 1/2 cups water
3 cups chicken broth
3 cups chopped carrot
1/4 cup half-and-half
1/2 tsp. salt
1/4 tsp. pepper
1/2 cup sour cream

Melt 1 Tbsp. butter in a large Dutch oven over medium heat. Add onion to pan, and cook until tender, stirring occasionally. Stir in cinnamon and nutmeg. Cook 1 minute, stirring constantly Move onion mixture to the side of the pan, and add remaining butter to the open space. Increase heat to medium-high heat. Cook 1 minute or until butter begins to brown. Add the potatoes, water, broth and carrots. Bring to a boil. Cover, reduce heat and simmer 35 minutes or until vegetables are tender. (Mine took much longer than 35 minutes.)

Place half the soup mixture in a blender. Remove center piece of blender to allow steam to escape, and process soup until smooth. Repeat with remaining soup. Combine blended soup with half-and-half, salt and pepper. Ladle about 1 cup of soup into each of 8 bowls. Top each serving with a small dollop of sour cream.