Cook the wild rice according to the package instructions; set cooked rice aside.

Meanwhile, melt 1 Tbsp of butter in a large Dutch oven or stock pot over medium heat. Add the diced onions and cook for 5-6 minutes, stirring occasionally, or until onions are slightly tender. Add the cinnamon and nutmeg; cook for 1 minute, stirring constantly.

Move onion mixture to one side of the pan. Add remaining 2 Tbsp butter to open space. Increase heat to medium-high and cook for 1 minute, or until butter begins to brown. Add sweet potatoes, water, broth and carrots. Bring mixture to a boil; then reduce heat and simmer (covered) for 35 minutes, or until vegetables are tender.

Using an immersion blender, puree the soup until smooth. (Note: If you don’t have an immersion blender, then you can puree this soup in a blender. Just puree half the soup at a time, but make sure to remove the center piece of the blender lid to allow steam to escape. Place towel over lid opening to avoid splattering. Blend until smooth. Repeat with remaining half of the soup.)

Stir in the cooked wild rice, half-and-half, salt and pepper; garnish with fresh thyme and sour cream (optional).