For phovu (aval): Heat a wide iron kadhai on medium heat.
Gently dry-roast the phovu on medium to low heat until crisp (12-15 minutes) and keep aside.
For happolu: Cut the happolu into 1/4 inch bits and deep-fry in hot oil. Keep aside.
For the kara boondi: In a bowl, mix gram flour, rice flour, red chilli powder, hing and salt with water and make a smooth batter (slightly thinner than dosa batter). Keep aside for 30 minutes.
Heat oil in a frying pan. Reduce the heat to medium. Pour the batter over a perforated ladle and gently shake the ladle, allowing the batter to fall through the holes of the ladle evenly into the hot oil.
Fry until golden and crisp. Drain out the boondis from the oil and place on a kitchen towel to absorb the extra oil.
For the peanuts: Mix the peanuts with salt.
Sprinkle 1 tsp of water and mix well. Keep aside for 20-25 minutes.
Heat oil in a frying pan. Reduce heat to medium and fry the peanuts until golden. Drain and place on a kitchen paper to absorb excess oil.
For the seasoning: Heat oil in a pan. Add mustard seeds. When they start spluttering, add jeera and saute for 2 minutes until fragrant. Add the green chillies and curry leaves. Fry for 3-5 minutes on medium heat until crisp and the colour of the green chillies has changed.
Add turmeric powder and hing. Stir well for 3-4 minutes on low heat or until the ingredients have combined well.
Final mixing: Transfer the dry-roasted phovu in a wide bowl and pour the seasoning (phann) over it.
Gently mix with a flat spatula until the seasoning and turmeric coat the phovu well.
Add salt slowly (just the right amount).
Add the deep-fried peanuts, kara boondi and fried happolu.