In a skillet, heat the olive oil over moderate heat. Add the onion, garlic, and ginger and cook for 3 minutes, or until the onion is translucent. Transfer the mixture to a 4- to 6-quart slow cooker.

Add the pumpkin and carrot over the onion mixture. Pour vegetable broth over the vegetables. Add the nutmeg, cinnamon, sea salt, and black pepper. Cover and cook on LOW for 6 hours.

With an immersion blender, blend the soup for 1 minute until smooth. (Alternatively, carefully transfer the ingredients to a blender and blend for 1 minute until smooth.)

Stir in coconut milk and the cold butter and stir until the butter is melted.

Divide the soup between 4 soup bowls and garnish with sunflower seeds.