Place the rice and both daals in a large bowl. Wash in plenty of cold water, changing the water 2-3 times. Drain well. Cover with 700ml cold water and soak for three hours.
Once soaked, drain the rice and lentil mixture completely, reserving 100ml of the soaking water.
Grind the soaked lentils and rice in a blender until completely smooth. Refer to the video to see exactly what kind of texture you need. You may need to add around 100ml water to the batter to help it grind properly. NOTE: DO NOT ADD MORE THAN 100ml water. Keep stopping the blender to scrape down the sides as necessary.
Pour the batter into a large pan or bowl. Add the semolina, yoghurt and fenugreek seeds. Beat well using clean hands - the heat from them will help speed up fermentation. Cover with a tight-fitting lid and leave in a warm place to ferment. This could take anywhere from 12 hours, to 24 hours depending on how warm it is. If it's a really warm day, it may take less than 12 hours. You'll know the mixture has fermented by the smell. Once it starts smelling a little sour, develops a layer of water on top, and bubbles appear at the sides, it's ready.
To prepare the fermented batter for baking:
Pre-heat the oven to 160°C/320°F. Grease a 20cm square tin with 2 tbsp any flavourless oil.
Squeeze all the water out of both the carrots and courgettes (or dudhi).
To the fermented batter, add diced potatoes, courgettes, carrots, peas, sweetcorn, onions, chilli, turmeric, ginger, salt, sugar and lemon juice. You may also add peanuts at this stage (if using). Mix everything well and set aside while you make the first tempering.
For the first tempering:
Heat the oil in a small pan. Add mustard seeds and allow them to finish popping. Finally, add the asafoetida and stir to incorporate. Switch the heat off.
Add the hot tempering to the prepared handvo batter. It will sizzle a little, so be careful. Whisk the tempering in.
To activate the batter (do this step immediately before the pouring the handvo into the tin and then bake immediately):
In a small bowl, mix together the bicarbonate of soda, baking powder and chickpea flour.
Add to the batter and whisk vigorously for 90 seconds. The batter will almost double in volume and turn a pale shade of yellow.
Immediately pour the batter into the prepared tin and bake for at 160°C/320°F for 90 minutes, or until a skewer inserted into the centre of the handvo comes out clean.
Remove from the oven and set aside. Increase the oven temperature to 200°C/400°F.
For the second tempering:
Heat the oil in a small pan. Heat the oil in a small pan. Add mustard seeds and allow them to finish popping. Next, add the sesame seeds, curry leaves and asafoetida and stir to incorporate. Cook for 15-20 seconds and then switch the heat off.
Carefully spoon this tempering all over the baked handvo, making sure the entire surface is covered. Add everything, including all of the flavourful oil.
Return the handvo to the oven for 5-10 minutes to brown the top to your liking. I like my handvo to have a deep, caramelised brown top.
Allow the handvo to cool in the tin for 1 hour before turning out. Cut into pieces and serve as a snack with hot chai.