In a large pot, heat the sunflower oil over medium heat. Add the red onion and bell pepper and cook, stirring frequently, until the onion is softened, about 5 minutes.
Adjust the heat to medium-low and add the sweet potatoes, carrots, garlic, nutritional yeast, smoked paprika, garlic powder, and cumin. Cook for 5 more minutes, adding 1 or 2 tablespoons (15 to 30 ml) water if necessary to prevent sticking.
Stir in the vegetable broth, water, and quinoa, cover, and bring to a boil over medium-high heat. Once boiling, adjust the heat so that the soup is simmering, cover, and cook, stirring occasionally, until the quinoa is tender, about 20 minutes longer.
Puree half of the soup mixture using an immersion blender or by carefully transferring to a blender. Add the spinach, stirring to break up any clumps, and add salt to taste. Let the soup cool for 20 minutes, then divide it between 5 jars or storage containers. Top each serving with the pumpkin seeds and cilantro and store in the refrigerator for up to 7 days. Serve with a slice of bread, if desired.
This soup is great for storing in the fridge to eat during the week, and it also freezes well if you want to plan way ahead. If you choose to freeze it, divide it into five freezer-safe storage containers and freeze for up to 6 months.