Prepare: Halve the pumpkin or squash and peel it (Hokkaido pumpkin doesn’t need peeling, but anything else does). Cut it into thick slices and then into cubes.
Peel and cube the sweet potatoes.
Peel and chop the onion, garlic, and ginger.
Saute: Heat the oil in a large pot. Saute the onion on medium heat for about 3 minutes or until translucent. Add the garlic, ginger, cumin, coriander, a few gratings of nutmeg, red chili flakes, salt, and pepper, and stir for 30 seconds.
Add the pumpkin and sweet potato cubes and stir for 2-3 minutes.
Simmer: Pour in the stock and the coconut milk. Cover, bring to a boil, and simmer for 15-20 minutes or until soft.
Blend the soup with an immersion blender (Note 2).
Roast the pepitas or pumpkin seeds (if not already roasted) in a dry pan for 2-3 minutes or until golden and fragrant. Once they start to pop, shake the pan frequently, and don’t let them unattended, they will burn quickly. Immediately transfer them to a plate.
Adjust the taste of the soup with salt, pepper, soy sauce, and lemon juice. Sprinkle it with seeds and chopped herbs and serve.