Prepare the potatoes: Scrub the potatoes. Steam or parboil them until half-cooked, then plunge into cold water to stop the cooking.
Once cool, dry them thoroughly and pierce each potato in 4 or 5 places with a fork to a depth of about 0. 5 inch / 1. 5 cm.
Deep-fry the potatoes: Heat ghee or oil in a deep pan to 365°F / 185°C.
Working in batches, carefully fry the potatoes until golden brown with a light crust.
Remove with a slotted spoon and drain on paper towels.
Create the masala paste: In a blender, combine the almonds and 0. 25 cup / 60 ml water and process until smooth.
Add the green chilies, ginger, turmeric, garam masala, ground coriander, and sugar.
Blend again until you have a smooth, thick paste.
Temper the spices: Heat 3 tbsp / 45 ml of ghee in a heavy-bottomed casserole dish over moderate heat.
Add the cassia or bay leaf and cumin seeds.
Fry for 30-60 seconds until the cumin darkens and becomes aromatic, then sprinkle in the asafetida.
Build the yogurt base: Reduce the heat slightly.
Whisk in the room-temperature yogurt in small amounts, stirring vigorously after each addition to prevent curdling.
Simmer the broth: Whisk in the prepared almond masala paste, 1 to 2 cups / 240-480 ml of water, and the salt.
Bring the mixture to a gentle simmer.
Add the fried potatoes and remove the pan from the heat.
The Dum (Slow Cook) Method: Preheat your oven to 300°F / 150°C. Lay a sheet of aluminum foil over the pot to create a tight seal, then place the lid on top.
Cook for 25 minutes.
Finish and serve: Remove the lid and foil.
Stir in the black pepper and optional heavy cream.
Transfer to a serving dish, garnish with fresh coriander, and serve hot.