Combine the first six ingredients in a saucepan and bring to boil.
Reduce heat and let simmer until pumpkin is tender. (For a lighter soup, omit onions and add more pumpkin).
Remove from heat and use a stick blender to blend until smooth. If you don't have a stick blender, use a blender and puree in small batches.
Add cooking wine and season to taste with salt and pepper. Add more mushroom seasoning if needed.