Heat 4 tablespoons of the oil in a wok or large pot.
Toss potatoes with turmeric and a little salt. Add to oil and fry until golden brown, tossing frequently, about 5 minutes.
Remove from pot.
Add the remaining oil to the pot. Add asoefetida, cumin seed and bay leaves. After cumin seed starts to change color, add chile and ginger paste. Fry for 1 minutes.
Add tomatoes and cook until they turn mushy, about 5 minutes.
Add cayenne pepper, 1 tablespoon of the garam masala, sugar and dhania-jeera powder. Fry for another 2 minutes.
Add grated coconut, coconut milk, salt and fried potatoes. Stir to combine and add 1 cup water. Bring to a boil.
Add the fried dhoka and stir to combine. Reduce to a simmer and cook for 5 minutes.
To serve, garnish with the rest of the garam masala.