Step 1: Preheat your oven to 400°F (200°C). Toss the diced butternut squash and apples with 2 tablespoons of olive oil, a generous pinch of salt, and freshly ground black pepper on a large baking sheet. Spread them in a single layer and roast for 25-30 minutes, or until fork-tender and slightly caramelized.
Step 2: While the squash and apples roast, heat the remaining 1 tablespoon of olive oil in a large, heavy-bottomed pot or Dutch oven over medium heat. Add the diced onion and sauté for 5-7 minutes until translucent and softened. Add the minced garlic and cook for another minute until fragrant.
Step 3: Stir in the ground nutmeg, ground cinnamon, and cayenne pepper (if using) into the pot. Cook for 30 seconds, stirring constantly, to bloom the spices.
Step 4: Add the roasted squash and apples to the pot. Pour in the vegetable broth. Bring the mixture to a gentle simmer, then reduce the heat to low, cover, and cook for 10-15 minutes, allowing the flavors to meld.
Step 5: Carefully transfer the soup mixture to a blender (working in batches if necessary). Blend until perfectly smooth and creamy. Return the blended soup to the pot over low heat.
Step 6: Stir in the heavy cream (or coconut milk) and fresh lime juice (if using). Taste and adjust seasoning with more salt, pepper, or spices as needed. Heat through gently.
Step 7: Ladle the hot soup into bowls. Garnish with toasted pumpkin seeds, fresh sage leaves, or a swirl of extra cream, and serve immediately with crusty bread.