Pressure cook cleaned dal with 1 cup water for 3-4 whistles on high flame. switch off the gas and let the pressure drop naturally. Open the cooker and drain the cooked dal. Keep it aside.
Combine coconut, 1 small onion, green chilli, cumin, garlic, and turmeric powder. Pulse it in the mixer for a few seconds with 1/2 tbsp water. It should be a coarse mixture.
Cook diced padavalanga with 1/4 – 1/3 cup water and salt for 15 – 20 mins. Cover and cook till it's done and water is dried completely.
Heat oil in a wide pan. Crackle mustard seeds. Add sliced small onion (6-8), dry red chilli and curry leaves. Fry for 2-3 mins.
Add coconut mixture and cook for 3-4 mins, till the raw smell goes.
Add cooked dal and padavalanga. Gently combine everything. Cover and cook for 2-3 mins. Remove from heat and serve with rice.