in a large saucepan, heat olive oil on medium heat. Once the oil is shimmering, add the chopped onion, stirring occasionally, until the onion is translucent, about 8 to 10 minutes.
Add the chopped pumpkin, sweet potatoes, and carrots, and cook for 5 minutes, stirring occasionally.
Add 4 cups water, sugar, and spices, stir well, put the lid on, and bring to a boil.
Lower heat and simmer for 20 minutes, until the veggies are very very soft.
Remove from the heat. Let the soup cool a little bit.
Using an immersion blender, blend the mixture until smooth. Or let the soup cool completely, then blend in a blender.
Stir in cream or coconut milk and season to taste if needed.
If the soup is too thick, add water or cream to thin. Taste and adjust salt and pepper if necessary.