Boil potatoes at least 2 hours ahead. Leave to cool. Just before cooking the dish, cube them into bite-sized pieces. Heat oil over a medium flame. Fry potatoes in small batches till golden brown on all sides. Drain & set aside. Save some of the oil for later use. Blend onion & garlic with 3 tb water. Heat 6 tb oil in large pot. When very hot, add asafetida, fenugreek, fennel, onion, & mustard seeds & bay leaf & red pepper in quick succession. Fry 20 seconds till bay leaf darkens. Add paste from the blender & turmeric. Fry, stirring for 5 minutes. Add tomatoes & sugar. Gently stir in 2 c water, salt & potatoes. Bring to a boil. Cover & simer for 10 minutes. Turn each potato over & simmer another 10 minutes. Serve hot.