Add the chopped pumpkin and chopped onion into the slow cooker, then pour over the vegetable broth.
Sprinkle in the minced garlic, cinnamon, nutmeg, and ginger to infuse the soup with warm spices.
Cover the slow cooker and cook on low for about 6 hours, until the pumpkin is soft and easily pierced with a fork.
Once cooked, use an immersion blender directly in the crockpot to blend the mixture until smooth and creamy. Alternatively, transfer the mixture to a food processor in batches and blend until velvety.
Pour in the heavy cream or coconut milk and stir well to incorporate, adjusting the texture and adding richness.
Taste the soup, then season with salt and pepper as needed, stirring to evenly distribute the flavors.
Garnish with fresh herbs, a swirl of cream, or toasted seeds, then serve hot for a comforting fall meal.
