Instructions:
- Preheat oven to 400°F (200°C). On a large baking sheet, toss the cubed squash, onion, garlic, 2 Tbsp olive oil, salt, and pepper. Spread in a single layer.
- Roast for 35–45 minutes, flipping halfway, until the squash is fork-tender and slightly caramelized. Add the whole sage leaves to the tray for the final 10 minutes of roasting to crisp them.
- While roasting finishes, melt the butter in a large stockpot or Dutch oven over medium heat. Add the thyme and cook for 30 seconds until fragrant.
- Add the entire roasted squash mixture (including the roasted garlic and onions) to the pot. Pour in the stock and stir well.
- Bring the mixture to a gentle simmer. Add the nutmeg. Simmer gently for 15 minutes to allow all the roasted and fresh flavours to combine thoroughly.
- Carefully blend the soup using an immersion blender until perfectly smooth and velvety. If using a standard high-speed blender, transfer in batches, ensuring the lid is vented to allow steam to escape.
- Return the soup to the pot (if necessary). Stir in the heavy cream, if using. Taste the soup and adjust seasoning, adding the teaspoon of cider vinegar or lemon juice for necessary brightness.
- Ladle the hot soup into bowls. Garnish immediately with the reserved crispy sage leaves and a drizzle of high-quality olive oil before serving.