Boil potatoes in salted water 8min until just tender. Drain. Heat 4 Tbsp oil over med-high heat, fry potatoes 5min until golden brown. Add turmeric and fry 30 seconds. Remove from the heat.
For sauce: Heat 3 Tbsp oil in another pan over a medium-high heat. Add the bay leaves, fry 1min. Add asafoetida and onion, fry 5min. Add garlic and ginger, fry 5min until soft and golden-brown.
Add spices (except garam masala) and salt, fry 1min. Add passata, chillies, and 100ml water and stir. Add fried potatoes, reduce the heat to medium, and cook covered 10min (add splash of water if needed).
Add peas and garam masala, cook uncovered 3-4min. Garnish with coriander and serve.