Take a wok peel the potatoes and deep fry them.When they turn golden brown take them out on an absorbent paper.Now take another wok add oil, cumin seeds, bay leaf. Let them crackle.Then add onion paste, garlic and ginger in it.Stir fry till it turns golden brown add salt,mango powder.Add tomato paste in it stir it on a very slow flame when the masala starts leaving oil.