Wipe the rice, toovar dal, urad dal, moong dal, gram dal, and wheat with wet cloth mix and grind dry coarsely.
Alternatively soak the cereals and pulses overnight in plenty of water and grind in a mixer the next day.
Add the sour curds and hot water and make into a thick mixture..
Cover and leave to ferment for atleast 6 to 7 hours.
Now add 4 tbdp oil, lemon juice, soda bi carb, sugar, chilli powder, turmeric powder and salt and mix well.
Spread this batter in a greased tin or metal plate with low rim.
For tempering heat oil in a pan and add the mustard seeds. After 1 minute add the sesame seeds and asafoetida. When brown in colour spread this oil over the batter.
Bake in a hot oven at 450°F for 30 to 35 minutes or till the crust is brown in colour.
For stuffing:- heat oil add saunf and khus khus.
Fry half of the chopped onions, add ginger, garlic and chilli paste and spices.
Add potatoes, salt a few coriander leaves and peanuts.
Cut the handvo horizontally with a thin thread or knife.
Apply chutney and sauce on both sides. Press the potatoes mixture on one side.
Sprinkle a little onion, sev and coriander leaves.
Cover with the the other half of the cake. Apply chutney and sauce.
Garnish with coriander leaves, onions and sev.
Cut a handvo into triangles. Serve hot.