Over medium heat, in a large Dutch oven, add butter, melt.
Once butter sizzles, add onions, carrots, celery. Saute for about 3-4 minutes. Add in the garlic and grated ginger. Saute another minute.
Stir in the vegetable broth and pumpkin puree. Add in the bay leaf, black pepper, Kosher salt, cinnamon, ground thyme, nutmeg, allspice.
Increase heat slightly to medium/ high. Bring the soup to a boil. Then reduce heat to low and simmer for about 15- 20 minutes.
Remove soup from heat. If using a blender, let rest about 10 minutes to cool a bit. Puree soup with an emulsion blender or place in a blender to puree soup till smooth. (See Note 4)
Return the soup to the Dutch Oven. Add in the cream. Warm soup for a minute or two. Check the seasoning, reseason if necessary. See Note 4