In one respect, the answer to the question raised by the title is easy: that the dish has its origins in India. The actual answer is a little more involved, and interesting.
India is an historic land, created from loads of unique cultures resulting from migration and invasion, followed by tribal merging. This is reflected in its cuisine. Everyone can identify something that is Indian about Indian food – the curry, the unique mix of a masala (Hindi for spice), the colourful chicken and lamb dishes, but every effort to pin it down somehow slips into a fog.
Think about the lowly chutney. This mix of fruit and spices could for certain have not come from anywhere else but India. What other land would have the inventiveness and courage to blend something sweet – i.e. ripe fruit – and mix in a mixture of spices?
To select another illustration, chicken is a familiar element of recipes from around the globe, but nowhere else but India invented that international favorite – tandoori chicken.
It isn’t just the sizzling hot clay oven. It isn’t simply the brilliantly coloured results that make the dish as much a pleasure to the eye as to the tongue, it is the pleasing mixture of spices and the unique method of preparation that contains them.
Lamb is a part of Greek and Italian cookery and that of many other nations. These places have a long history and many alliances and neighbouring cuisines to draw upon but the difference between an Indian Achari dish and a Greek lamb stew is exceptional.
Maybe it is the coriander, but that appears in Greek cooking too. Tomatoes are an daily component of Greek dishes, too. Could it be the tasty spices which make Indian dishes so different? Not really, because the ancient Greeks moved around the world and brought back many ingredients from far afield. Whichever way you look at it Achari is exotic, vital and pungent whereas Greek stew is delicious, but mild.
Even the common doughnut is renowned as far apart as both China and America. Yet, Indian vada bears no resemblance to its counterparts in other countries. The oil-fried dough in America is a solely sweet, fat-filled confection. In China, it is usually the savoury meal itself, dim sum. In India, it is a respected part of the street vendor culture.
For all you can point to that singles out Indian cuisine – the vigorous spices, the eye-catching presentation, the thin, hard bread – the answer to what makes Indian food Indian will still remain a mystery. Given the country in question, that seems wholly appropriate.