Rinse 200g of moong dal and 30g of rice. Soak in abundant water for 4 to 6 hours or overnight until completely plump.
Drain water. Blend the soaked mixture with ginger, green chilies, cumin seeds, salt, and about 1/2 cup of water until smooth but finely textured.
Heat a cast-iron tawa on medium. Test with water drops to ensure it sizzles, then wipe clean with a lightly oiled cloth or onion half.
Pour a ladle of batter in the center. Gently but swiftly swirl outward in circles to form a thin, even crepe.
Immediately sprinkle chopped onions and a drizzle of ghee around the edges. Press the onions down gently with a spatula.
Cook until the bottom turns speckled golden-brown and crispy. Fold in half and serve hot.
