Clean and wash toovar dal. Pressure-cook with salt, turmeric and water. Cool and mash well. Keep aside. Wash and chop tomato. Peel and wash pearl onions. Wash and pat dry curry leaves.
Remove stems and break whole red chillies into smaller pieces. Heat oil in a pan and add mustard seeds, broken red chillies, curry leaves and asafoetida. When mustard starts to crackle add chopped tomatoes and cook for two to three minutes.
Add pearl onions and sambhar powder and stir-fry for another four to five minutes. Pour in the dal. Mix well. Add jaggery and tamarind pulp and simmer for another five to ten minutes.
Serve hot with steamed rice.