Heat the olive oil in a large pot over medium heat. Add the onion and cook for 5 to 6 minutes, stirring occasionally, until softened.

Add the garlic and ginger and cook for 1 minute, until fragrant.

Stir in the tomato paste, cumin, smoked paprika, and cayenne pepper. Cook for 30 seconds to bloom the spices.

Add the butternut squash, sweet potatoes, vegetable broth, water, salt, and black pepper. Bring to a boil, then reduce the heat to low, cover, and simmer for 20 to 25 minutes, or until the vegetables are very tender.

Remove the pot from the heat. Use an immersion blender to puree the soup until smooth, or carefully blend in batches in a countertop blender.

Stir in the coconut milk and lime juice. Taste and adjust seasoning with more salt or cayenne if needed.

Ladle the soup into bowls and garnish with chopped cilantro and a drizzle of coconut milk, if desired.