Heat olive oil in a large pot over medium heat. Add onion, carrots, and celery and cook 6–7 minutes until soft. Add garlic and cook 2 minutes. Stir in tomato paste and cook 1 minute. Add all spices and stir 30 seconds.
Pour in crushed tomatoes and vegetable broth. Add rinsed red lentils and stir to combine. Bring to a boil then reduce to a steady simmer.
Cook uncovered for 20–25 minutes, stirring occasionally, until lentils are completely soft and broken down into the broth and the soup has thickened. Stir frequently in the last 5 minutes to prevent sticking.
For a smoother texture, use an immersion blender to partially or fully blend the soup. Leave it chunky, half-blended, or fully smooth — all versions work.
Stir in lemon juice. Taste and adjust salt and pepper. Ladle into bowls, drizzle with olive oil, and top with fresh parsley or cilantro. Serve with crusty bread and lemon wedges on the side.
