In a large pot, preheat the oil at medium heat for 2-3 minutes.
Add the onions. Season lightly with salt and pepper. Sauté for 5 minutes. Add the garlic and sauté for 1 more minute. Add the lentils and sauté for 1 more minute.
Pour in the salsa and 3 cups of the broth. Stir well to combine. Bring up to a light simmer and cook for 10 minutes. Add the potatoes, cumin and remaining broth. Stir well to combine. Taste for salt. Cook for 10 minutes.
Fold in the cilantro. Continue cooking until lentils and potatoes are cooked through and tender. Cook time on my stove was approximately 42 minutes from the time the lentils begin to simmer. Yields 6 servings.