Rinse the lentils under cold water in a fine-mesh strainer and set aside to drain.

Finely chop the onion, garlic, carrots, and celery to create a flavorful base.

Heat olive oil in a large pot over medium heat, add the chopped vegetables and sauté for about 5 minutes.

Add the spices (cumin, smoked paprika, chili flakes) and toast for an additional minute.

Stir in the crushed tomatoes and cook for 2-3 minutes.

Pour in the rinsed lentils and vegetable broth, bring to a gentle boil, then simmer for 20 minutes.

Check for tenderness, continue simmering if necessary until lentils are desired texture.

Season with salt, pepper, and stir in fresh herbs if desired before serving.