1. Soak lentils for 2 hours.
2. Warm olive oil in large pot over medium heat. Add chopped onion and carrot and stir until onion is soften and turned translucent.
3. Add garlic, bay leaf and cumin. Stir and cook until fragrant. Pour in lentils, water, diced tomato, salt and red pepper flakes. Season with black pepper.
4. Raise heat and simmer for about 1 hour.
5. Remove pot and stir in 1 tbsp of lemon juice. Serve while hot.