Preheat oven to 400°F (200°C) and line a large baking sheet with parchment paper. Place cubed butternut squash and chopped onion on the sheet. Drizzle with 2 tablespoons olive oil and toss with salt, black pepper, cinnamon, and nutmeg until evenly coated.

Place the trimmed garlic head on a piece of foil, drizzle the exposed cloves with olive oil, and wrap tightly in the foil. Place foil packet onto the baking sheet alongside the squash.

Roast for 35 to 40 minutes, tossing squash once halfway through, until squash cubes are fork-tender with caramelized browned edges and garlic cloves are golden and buttery-soft.

Transfer roasted squash and onions into a large Dutch oven or heavy pot over medium heat. Squeeze the roasted garlic cloves out of their skins directly into the pot, discarding the papery skins.

Pour in the chicken broth and bring soup to a gentle simmer for 5 minutes to let flavors meld.

Use an immersion stick blender to puree the soup directly in the pot until completely smooth, silky, and velvety. (Alternatively, transfer in two batches to a high-speed countertop blender and blend until ultra-smooth, then return to pot).

Reduce heat to low and stir in the heavy whipping cream, pure maple syrup, and apple cider vinegar. Simmer gently for 2 to 3 minutes until heated through. Taste and season with additional salt and freshly cracked black pepper as desired.

In a small skillet, melt 3 tablespoons of butter over medium heat. Once bubbling, add fresh sage leaves in a single layer. Fry for 45 to 60 seconds until leaves are crisp and fragrant and butter turns golden brown with a nutty aroma. Immediately transfer sage leaves to a paper towel.

Ladle hot butternut squash soup into serving bowls. Swirl each bowl with a splash of heavy cream, drizzle with the fragrant browned sage butter, and top with crisp sage leaves and toasted pepitas. Serve immediately with warm crusty bread!