Heat a pot on medium heat
Once heated, add the olive oil and diced onions and sauté until the onions are translucent and soft
If you're adding carrots and celery, add them to the pot once the onions are cooked through—sauté until carrots begin to get soft
Add the lentils to the sautéed onions and veggies and stir
Add 4 cups of water to the pot
Stir in the spices (cumin, turmeric, salt, and black pepper) using a whisk
Once the water comes to a boil, reduce the heat to low and cover the pot
Stir the lentils occasionally and continue adding water as it dries up
Allow the lentils to cook for about 45 minutes or until they are completely soft
Remove from the heat and stir in lemon juice
Serve with sliced lemon, dakkah, and mana'eesh or fatayer