You can shave at least 50 minutes from the cooking time by starting with canned unsweetened pumpkin puree. You'll need a 29-ounce can.
3 lb. pumpkin
2 tbsp. olive oil
1 carrot, chopped
1 stalk celery, chopped
1 small onion, chopped
1 garlic clove, minced
1/2 tsp. dried marjoram, crushed
4 cups fat-free, lower-sodium chicken broth
1/2 lb. cooked chorizo, diced
1 can (12 oz.) fat-free evaporated milk
Kosher salt and freshly ground black pepper
1. Preheat the oven to 350°F. Line a baking sheet with foil.
2. Halve pumpkin, scoop out seeds and membranes, and place halves cut-side down on baking sheet. Bake until tender, about 40 minutes. When cool enough to handle, scoop out flesh and coarsely puree in a blender or food processor.
3. In a heavy saucepan or Dutch oven, heat oil over medium heat. Add carrot, celery, onion, garlic, and marjoram and cook until onion begins to wilt, about 5 minutes. Add broth and pumpkin puree. Reduce heat and simmer for 15 minutes.
4. Remove from heat and let cool slightly. In batches, puree cooled soup in a blender. Return blended soup to saucepan and add chorizo. Over medium heat, simmer until thoroughly heated. Stir in evaporated milk and cook for 2 minutes. Season with salt and pepper to taste.