In a large pot, heat a tablespoon of olive oil over medium heat. Add chopped onion, carrot, and celery stalk. Cook for about 5–7 minutes, until softened and fragrant.

Sprinkle in cumin and coriander, stirring for an additional 1–2 minutes to toast slightly, enhancing their aroma.

Introduce rinsed lentils and diced tomatoes into the pot, mixing well to combine.

Pour in the broth and bring the soup to a rolling boil.

Reduce heat to low, cover the pot, and let the soup simmer for about 25 minutes, until lentils are tender.

Stir in freshly chopped parsley and adjust seasoning with salt and pepper. Serve warm.