Preparation Time:6-8 hours
Wash the urad dal and moong dal (if using) 2-3 times in water. Soak the dal in enough water for 4-6 hours or overnight. Drain the water and transfer the soaked dal to a blender or wet grinder. Add very little water (just a few tablespoons) and grind the dal into a smooth, fluffy batter. The batter should be thick. Add salt, grated ginger, green chilies, cumin seeds, and a pinch of asafoetida to the batter. Mix well.
Whisk the batter well for 2-3 minutes to incorporate air, which will make the bhallas light and fluffy. Heat oil in a deep frying pan on medium heat. Wet your hands slightly and take small portions of the batter (about a tablespoon each) and carefully drop them into the hot oil. Fry the bhallas on medium heat until they are golden brown and crispy on all sides. Remove the bhallas from the oil and place them on a paper towel to drain excess oil.
Once the bhallas are fried, immediately soak them in a bowl of lukewarm water for 15-20 minutes. This will make them soft and spongy. After soaking, gently press each bhalla between your palms to remove excess water. Be careful not to break them.
Refrigerate the dahi bhallas for at least 30 minutes before serving to allow the flavors to blend. Serve chilled for the best taste.
