Sauté veggies: Add olive oil to a pot over medium heat. Once hot, sauté onion for 5 minutes. Add carrots, celery, garlic, and ginger and sauté a few more minutes.
Add lentils, chickpeas, tomatoes, spices and vegetable broth. Bring to a boil, stirring occasionally, then reduce heat and simmer for about 30-35 minutes, or until lentils are tender.
Thicken: Use an immersion blender to puree the soup just a little bit, to add a thick and creamy texture (or blend half of the soup in a food processor or blender).
Stir in vinegar and season with salt and pepper, to taste.
Garnish with fresh chopped cilantro, crushed red pepper flakes and feta cheese when serving. Serve with pita bread, if desired.
