Halve the pumpkin and remove the seeds. If using anything else but Hokkaido, peel the pumpkin as well. Slice it thickly and cut the slices into cubes.
Vegetables: Peel and cube the potatoes. Chop the onion and peel the garlic cloves but leave them whole.
Sauté: Heat the oil in a large soup pot. Sauté the onions for 2-3 minutes until translucent. Add the garlic cloves, pumpkin, and potato cubes, stir and sauté for about 5 minutes.
Simmer: Add the stock and rosemary sprig and bring it to a boil. Turn the heat down to low and simmer the soup, covered, for 15-20 minutes or until the vegetables are soft.
Roast pepitas: In the meantime, roast the pepitas if they are not already toasted.
Blend soup: Remove the rosemary sprig and blend the soup with an immersion blender (Note 4).
Add the cream and reheat gently without letting the soup boil again.
Adjust the taste with salt and pepper. Serve the soup topped with roasted pepitas and potato croutons.