I recommend soaking the lentils in lukewarm water for 20 minutes if you are using green or brown lentils (not red lentils). The lentils will cook faster and are better digested when soaked.
Heat oil in a pan or pot over medium heat. Add the onion, celery, mushrooms, and carrots, and sauté for 3–4 minutes. Stir in the garlic, sweetener, and a