Heat the olive oil in a medium saucepan over medium heat. Add the onion, garlic, carrot and celery and cook for 10 minutes, stirring often, until the vegetables are just softened.

Add the spices, cumin and paprika, and let cook for a minute until fragrant.

Add in the lentils, tomatoes, broth, and bay leaf and bring to a boil. Reduce heat to low and cook for 20-25 minutes, until lentils are softened. Season, adding the salt.

Depending on your preferred texture, stir in the lemon juice and serve or remove 1-2 ladles of the soup and puree in a small blender, then return back to the pot along with the lemon juice.