In a large pot, heat the olive oil over medium heat.
Add the onion and garlic, cooking until softened, about 2 minutes. Then mix in the spices and continue to sauté for another 4 minutes.
Put in the carrots and celery, cooking until the carrots are tender, roughly 10 minutes. Then pour in the vegetable broth and add the lentils, stirring well.
Reduce heat to low and let the soup simmer for 20 minutes, or until the lentils are soft.
Stir in the lemon juice and, if desired, the lemon zest for an extra citrus kick.
For a smoother texture, use an immersion blender or transfer to a blender to puree the soup to your liking. You can blend all of it or just half to keep some texture.
Garnish and serve. Ladle the soup into bowls and top with fresh cilantro, dill, and lemon wedges on the side.