As the name suggests refers to the vaal dal which are boiled. You can use two cups of water per cup of lentils. These proportions are based on cooking with the pot cover on. This way, it will cook a little faster, use less energy, and perhaps retain more vitamins. Bring the concoction to a boil, then turn the down the flame to medium-low. If it gets too thick, add more water. The beans are cooked when they burst and the water turns syrupy. You can also pressure cook the soaked vaal dal with or without salt in boiling water for 3-4 minutes. The beans are cooked when they burst and the water turns syrupy. At this point , you may add spices or vegetables as per your preference and recipe requirements.