Wash and soak a mix of split yellow moong dal and urad dal in water for 4-5 hours. Drain and grind to a smooth, thick batter using minimal water.
Add salt and whisk the batter well to make it light and fluffy. Then add chopped green chilies, grated ginger, cumin seeds and mix well. Batter is ready to make bhallas.
Heat oil in a deep pan for frying. carefully drop small portions of the batter with help of fingers or use spoon into the hot oil and fry until golden brown. Fry bhallas in a small small batches, 5-6 at a time.
After frying, soak the bhallas in warm water with little salt diluted in the water for 30 minutes, cover and keep aside then gently squeeze out the water and set aside.
Whisk chilled yogurt with little salt, then add little water and mix well, yogurt mixture should be pourable but not thin.
Dip crispy papdis briefly in chilled yogurt and few papdis in the sweet chutney for added flavor.
Arrange the dipped papdis on a serving plate as the base layer.
Break soaked bhallas into small pieces with your hand, then spread on top of the yogurt-dipped papdis.
Generously drizzle fresh, chilled yogurt over the bhallas and papdi.
Spread cubed boiled potatoes and chana on top for extra texture and heartiness.
Add a layer of sweet tamarind chutney and green chutney as per your taste.
Sprinkle chaat masala, roasted cumin powder, chili powder and black salt over the layers for an authentic flavor.
Garnish with sev, pomegranate seeds, and a dash of finely chopped green chilies if you prefer extra heat.
Just before serving, add a final drizzle of yogurt and chutneys, crushed papdis and sprinkle with a touch more of chaat masala and cumin powder for an aromatic finish.
You can use same method and make individual serving jar or cups to arranging layers of papdi, bhallas, yogurt, chutneys, boiled potatoes, chana and spices with garnish on top in the small glass jars or cups.