There is no Indian cuisine. There is a subcontinent of them — divided by region, faith, climate and language, from the wheat and dairy of the Punjab to the rice, coconut and ferment of the Tamil south, and they do not cook alike. What holds them together is not a dish but a way with spice.
Spice here is architecture, not heat. The cook toasts, grinds, blooms and layers — the masala built for one dish, the tadka of whole spices bloomed in hot fat and poured over at the end. Get the sequence and the timing right and a handful of the same spices becomes a hundred different dishes; get it wrong and they collapse into one. That control is where the dish lives or dies.
Two great streams run through it: the Mughal refinement of the north, with its slow dum cooking, its biryani and its enriched gravies; and the Dravidian south, built on rice, coconut, tamarind and the daily genius of the fermented dosa and idli batter. The diaspora has carried this food to every city on earth — and flattened much of it into a single word, "curry," that means nothing precise. The work of the canon is to give the regions their names back.