Heat olive oil or butter in a large pot over medium heat.
Sauté onions and garlic until fragrant and slightly golden.
Add sweet potatoes and stir for 1–2 minutes.
Pour in broth and bring to a boil, then reduce heat and simmer until potatoes are soft (15–20 minutes).
Add cinnamon, nutmeg, salt, and pepper; stir well.
Blend soup until smooth using an immersion blender or regular blender.
Stir in coconut milk and warm through for 2–3 minutes.
Serve in bowls and garnish with pumpkin seeds, cream, or parsley.