Direction :

1. Preheat the oven to 350ºF. Line a sheet pan with parchment paper (for easier cleanup).
2. Halve the butternut squash: slice off the bottom of the bulbous end, stand the squash upright, then carefully cut straight down through the center. Use a spoon to scoop out the seeds and discard. Rub the halved sides with a drizzle of olive oil then place them halved side down on the prepared sheet pan. Cut the head of garlic in half through the equator. Rub a small amount of olive oil on the sheet pan and place the garlic, cut side down, in the olive oil. Transfer to the oven.
3. After 40 minutes, check on the garlic. If it is knife-tender and caramelized at the surface, remove it, otherwise, let it continue roasting with the squash until done. Cook the squash for roughly 1 hour or until knife tender at the solid end. 
4. Let the squash and garlic cool for 20 minutes or until cool to the touch. Scoop the squash flesh into a pot. Squeeze the roasted cloves of garlic into the pot as well. Add the quart of stock. Bring to a simmer.
5. Use an immersion blender to purée the mixture — alternatively, transfer the mixture to a blender or food processor and purée until smooth. If you transferred the mixture to puree it, return it to the pot and bring it to a simmer. Taste. Adjust to taste with salt and pepper to taste. I consistently add 1 to 1.5 teaspoons of Diamond Crystal kosher salt. 
6. If you wish, add the heavy cream or crème fraîche and whisk to incorporate. Depending on the size of the squash, you may need to add more stock to thin it to the right consistency. 
7. Ladle into bowls and serve with bread on the side. 
8. Store the soup in the fridge for up to a week or freeze for up to 3 months. When reheating day- or days-old soup, you may need to add water or more stock to thin — it thickens as it sits.