The garnishes of pumpkin seeds, cilantro, and pickled red onions give it just the right amount of bright flavor and interesting texture to keep you coming back for another bite.
If making the pickled onions, prep those before starting the soup. In a small bowl of glass jar combine the red wine vinegar, water, and salt. Stir until salt is dissolved. Add onions and set aside.
Heat olive oil over medium heat in a large soup pot. When hot, add the diced yellow onion, diced fennel, carrots, and thinly sliced garlic. Cook, stirring occasionally, until soft.
Add coriander, paprika, cumin, chili flakes (if using), salt, and pepper. Cook for another minute or so, stirring frequently, until spices are aromatic.