Pressure cook the potato with water, turmeric powder, and salt for 1 whistle
Drain the water and cool
peel the skin and roughly smash
Add besan flour, sambar powder, and salt; mix and rest
Heat coconut oil and temper mustard seeds, Chana dal, and curry leaves
Add onion and saute till onion turns translucent
Add marinated potatoes; cook in low-medium flame for 8-10 minutes