Prepare the pumpkin and vegetables: Peel and cube the Jarrahdale pumpkin. Chop the onion, garlic, carrots, and celery.
Sauté the vegetables: In a large pot, heat olive oil over medium heat. Add the chopped onion and garlic, cooking until softened (about 3-4 minutes). Add the carrots and celery, cooking for another 5-7 minutes.
Add pumpkin and broth: Stir in the cubed pumpkin and pour in the vegetable broth. Bring the mixture to a boil, then reduce to a simmer. Cook for 20-25 minutes or until the pumpkin is tender.
Blend the soup: Use an immersion blender to blend the soup until smooth, or carefully transfer the soup in batches to a regular blender.
Add creaminess and seasoning: Stir in the coconut milk (if using) and season with salt, pepper, nutmeg, and cinnamon. Simmer for 5 more minutes.
Serve and garnish: Ladle the soup into bowls and garnish with fresh herbs. Serve hot.
