Heat the olive oil in a large soup pot over medium heat.
Add the cumin seeds and toast for 1 minute, making sure not to burn.
Add the onion, garlic and saute for 2-3 minutes.
Add the ginger, cinnamon, cloves, allspice, cayenne, curry powder, salt and pepper, and toast the spices for another 2 minutes.
Add the pumpkin puree, vegetable stock (or you can use chicken stock, if you're making this for a fleishig meal), and light brown sugar . Taste the soup and adjust seasonings if needed.
Simmer the soup for 45 minutes on low-medium until all of the flavors meld together.
Using a handheld immersion blender, blend the soup until smooth. If you don't have an immersion blender, you can ladle the soup into a few batches into your blender - make sure not to fill your blender to the top, as you want some heat to escape.
Pour the soup back in the pot (if using a blender), and add the non-dairy milk (or heavy cream, if making a milchig meal) and lemon juice.
Ladle into bowls and garnish with freshly snipped chives, or sprinkle with parve popcorn!