Special Equipment: large rimmed baking sheet; parchment paper.

Position an oven rack in the center of the oven and preheat the oven to 400ºF/200ºC. Line a large rimmed baking sheet with parchment paper.

Cut the pumpkin in half and use a soup spoon to scrape out the seeds and fibers. Cut the apples in half and core them. Peel the shallots, remove the root end, and cut them in half. Generously brush the interior meat of the pumpkin halves with olive oil and sprinkle salt and pepper over them before placing them cut side down on a rimmed baking sheet. Brush the cut sides of the apples and shallots with olive oil, and arrange them cut side down beside the pumpkin. Roast the tray of pumpkin, apples and shallots until the pumpkin is tender when pierced with a fork, about 30 minutes. (By then, the apples will have burst from their skins and the shallots will be tender.)

Use a spoon to scrape out the meat of the pumpkin and apples (discard the skins) and put it in the blender along with the roasted shallots. Add 2 cups of the broth and blend on speed 1 until pureed, about 1 minute (scraping down the sides of the blender half way through). Pour half the mixture into a soup pot, then add the remaining broth to the blender, along with the cream, sugar, nutmeg, and cayenne. Blend on speed 1 until smooth and well incorporated. Add this mixture to the pot and stir to incorporate. Bring the soup to a low simmer before serving.

While the soup is heating, make the sour cream garnish. In a small bowl, combine the sour cream with 1 Tbsp of water or broth. Whisk to a consistency that can be easily drizzled or poured, adding slightly more liquid, if needed.

To serve, drizzle or swirl the soup with the sour cream garnish, and sprinkle toasted pepitas over top.