Heat the oven to 425°F (220°C). Toss the pumpkin wedges, onion and garlic with 2 tbsp olive oil, the salt and pepper on a sheet pan.
Roast 40 to 45 minutes, until the pumpkin is very soft and browned at the edges. Wrap the garlic in foil if it starts to burn.
Scoop the pumpkin flesh away from the skin. Squeeze the garlic out of its skins.
Warm the remaining 1 tbsp oil in a large pot. Add the cumin, nutmeg and cayenne and stir for 30 seconds.
Add the pumpkin, onion, garlic, stock and maple syrup. Simmer 10 minutes.
Blend until completely smooth with an immersion blender, or in batches in a blender with the lid vented.
Stir in the cream and vinegar. Taste and adjust salt. Thin with more stock if needed.
Serve topped with a swirl of cream, toasted pumpkin seeds and thyme.
Notes
Canned shortcut: use two 15-oz cans of pumpkin puree instead of roasting. Sauté the onion and garlic in the pot first, then continue from step 4. Simmer 15 minutes.Vegan: use vegetable stock and coconut milk.Storage: fridge 4 days, freezer 3 months (freeze before adding cream if you can).