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Retrocop - I have a book called the Curry Secret which has recipes for Indian restaurant cooking which is very different from Indian home cookery. As you probably know, Indian restaurants make a gravy base from onion, ginger and garlic. It takes ages to boil down. Then they add spices to make a basic curry sauce. Then they add the appropriate spices according to which curry the customers order. That is why they can knock up a curry so quickly. The guy on that website that I linked has found a way to dehydrate the basic curry gravy. There are quite a lot of premixed spices that can be bought but to my knowledge, nobody has managed to get the consistencey right. His curries do come out a bit on the hot side though.