Prepare the Vegetables: Peel and chop the carrots, sweet potato, and pumpkin into similar-sized pieces for even cooking. Dice the onion.
Sauté the Aromatics: Heat a large saucepan over medium heat. Spray with low-calorie cooking spray and sauté the onion for 3-4 minutes until softened. Add the garlic, cumin, coriander, and paprika, and cook for an additional minute. Add a splash of water if things start to stick.
Cook the Vegetables: Add the carrots, sweet potato, and pumpkin to the pan. Stir well to coat in the spices.
Add the Stock: Pour in the vegetable stock. Bring to a boil, then reduce the heat to a simmer. Cover and cook for 20-25 minutes, or until all the vegetables are tender.
Blend the Soup: Use a hand blender to purée the soup until smooth. Adjust the consistency with a little extra stock or water if needed. Season with salt and pepper to taste.
Serve: Ladle the soup into bowls and garnish with freshly cracked black pepper or a sprinkle of chopped parsley, if desired.