Preheat oven to 425°F (220°C). Line a large rimmed baking sheet with parchment paper.

Brush cut surfaces of halved squash, cored apple halves, quartered onion, and exposed garlic head with olive oil; season with kosher salt and black pepper.

Place squash and apple cut-side down on the sheet pan. Wrap garlic loosely in foil. Roast for 40 to 45 minutes until the squash flesh is deeply golden-caramelized and fork-tender.

Allow vegetables to cool for 5 minutes. Use a large spoon to scoop tender caramelized squash flesh directly out of the skins into a Dutch oven or large soup pot.

Add roasted apple halves, roasted onion, and squeeze the sweet roasted garlic cloves out of their paper skins into the pot.

Pour in warm vegetable broth, fresh sage leaves, and freshly grated nutmeg. Bring to a gentle simmer over medium heat for 5 minutes.

Remove pot from heat (discard sage leaves if you prefer milder herbal note, or leave in for robust flavor).

Using an immersion hand blender directly in the pot (or working in batches in a high-speed countertop blender), puree for 60 to 90 seconds until completely silky, glossy, and lump-free.

Stir in heavy cream and pure maple syrup over low heat until gently warmed through (do not boil once cream is added). Taste and adjust seasoning with salt and pepper as needed.

Ladle steaming soup into warm stoneware bowls. Drizzle with an extra swirl of cream, scatter toasted crunchy pepitas, and crown with crispy pan-fried sage leaves.