In a large pot over medium heat, gently melt the butter with the olive oil, making sure the butter does not brown. Add onion, carrots, and celery, and sauté until softened, 6–7 minutes. Stir in the garlic and cook for 1 minute.

Add the butternut squash, potato, salt, black pepper, nutmeg, and cayenne (if using). Stir to coat the vegetables.

Pour in the broth. Bring to a boil, then reduce heat and simmer 20–25 minutes, until the squash and potato are fork-tender.

Blend the soup until smooth and creamy. Use an immersion blender directly in the pot, or carefully transfer the soup to a blender in batches. If using a blender, return the pureed soup to the pot once blended.

Stir in the cream, maple syrup, and lemon juice. Taste and adjust seasoning with additional salt and black pepper, if needed.

Ladle into bowls and serve hot with your favorite toppings.