Roast the pumpkin (if using fresh): Preheat your oven to 400°F (200°C).
Halve the pumpkin, scoop out seeds, and place cut-side down on a lined baking sheet. Roast 35–45 minutes, until fork-tender. Scoop out the flesh and set aside.
Sauté the aromatics: In a large pot, heat butter and olive oil over medium heat.
Add the onion with a pinch of salt and cook 5–7 minutes until soft and translucent. Stir in the garlic and cook 30 seconds, just until fragrant.
Bloom the sage: Add chopped sage to the pot and cook 30–60 seconds. This step deepens the flavor and infuses the fat with sage.
Add pumpkin and broth: Stir in roasted pumpkin (or canned purée) and pour in the broth.
Bring to a gentle simmer and cook for 10–15 minutes so the flavors mingle.
Blend until silky: Use an immersion blender to purée the soup right in the pot until smooth. If using a countertop blender, work in batches and vent the lid slightly to release steam. Return the soup to the pot if needed.
Finish with cream and spices: Stir in the cream, nutmeg, and a good pinch of salt and pepper.
Simmer on low for 3–5 minutes, but don’t let it boil hard.
Adjust and brighten: Taste and add more salt or pepper as needed. Stir in lemon juice to brighten the flavor. Add a splash more broth if you want a thinner consistency.
Optional crispy sage garnish: In a small skillet, heat a thin layer of olive oil.
Fry whole sage leaves for 10–15 seconds until crisp. Drain on paper towels and sprinkle with salt.
Serve: Ladle into warm bowls and garnish with a swirl of cream, crispy sage, toasted seeds, or a pinch of chili flakes for heat.