Cook toor dal with garlic, green chillies, Cinnamon, turmeric, required salt and enough water for 5 minutes in a pressure cooker. Keep cooked dal aside.
Meanwhile, heat oil in a pan and splutter mustard seeds. Add cumin seeds, red chilly flakes, fenugreek seeds and chopped onion. Fry well till onion turns golden in color.
Stir in chopped fenugreek leaves and tomatoes. Toss well and cook in medium flame for 10 minutes.
Add cooked dal and mix well. Add required salt and water if required, to maintain a gravy consistency. Cover and cook in low flame for 8 minutes. Sprinkle lemon juice and remove pan from fire.
Dal with fenugreek leaves, a yummy as well as nutritious recipe, is ready. Serve hot with rice/chappathis.