Preheat the oven to 350 degrees F. Line a baking tray with parchment paper and keep it aside.
Peel the skin and remove the seeds from the butternut squash. Chop the butternut squash into 1-inch squares. Transfer them to the tray.
Add the carrots, onions, and cloves to the same tray.
Toss the olive oil over the veggies along with the spices; salt, black pepper, cayenne pepper, nutmeg, and thyme. Coat them well.
Place it in the oven and roast for 1 hour until the veggies are soft and tender.
Heat a heavy bottom pot over medium heat and add butter. Once the butter is melted add the roasted veggies along with the chicken broth. Let them simmer for 4-5 minutes.
Using an immersion blender, puree the soup until smooth and creamy. If the soup consistency is thick add some more broth to make it a little thin.
Serve the butternut squash soup while it is still warm with bread croutons on top.