Method

Make vadas: Coarsely grind soaked chana dal with dried red chillies and salt (some texture is preferred — not smooth). Add fennel seeds. Shape into flat patties or rough balls. Deep-fry in hot oil until golden. Cool and break/crumble into rough chunks (not too fine — you want chunks).
About 20 min
Tip: Leave texture in the vada batter — smooth batter makes dense vadas that don't absorb curry well. Chunky vadas soak up the gravy and swell beautifully.
Make curry: Heat 2 tbsp oil. Add mustard seeds and curry leaves. Add onion — cook 8 minutes. Add ginger-garlic paste — 2 minutes. Add tomatoes and turmeric — cook 5 minutes. Grind coconut with a little water to paste and add — fry 3 minutes. Add coriander powder. Add 300ml water and bring to boil.
About 15 min
Tip: The curry base should be fairly thick — vadas will absorb liquid as they soak, so start with a thicker curry.
Add the crumbled vadas to the simmering curry. Simmer 8–10 minutes until the vadas are soft and have absorbed the curry. The curry should have thickened around the vadas. Garnish with fresh coriander. Serve with fluffy idli or soft puri. Excellent with coconut chutney on the side.
About 10 min
Tip: Leave on low heat for the last 5 minutes without stirring — let the vadas slowly absorb. Stirring too much will disintegrate them.

Nutrition per serving (estimate)