Last week we took a friend who is leaving Mumbai soon to Madras Café in Matunga. As insurance for her return, we ate the staples of this legendary little restaurant that has nourished the reputation of Madrasi cuisine among Mumbai’s other communities for decades (the servers and I were probably the only south Indians in the joint). We dispatched our brunch with the same grim efficiency as it was served: the vadas, idlis and dosas flew down the hatch. We were hungry; there were other customers waiting to be seated.

A touch of Maghreb: Indigo Deli’s version of the upma has couscous. Abhijit Bhatlekar/Mint

It may be easier to define what upma is not, than what it is. Mumbai-born Floyd Cardoz, the former executive chef of New York’s fancy Tabla restaurant, called his mushroom, kokum and coconut upma a polenta (some intrepid Tamilian probably made it to Milan in between the Goth invasions). He might have had a tough time impressing a child opening her break-box at school, but it pleased the judges of Top Chef Masters, the prestigious Los Angeles-based celebrity cook-off, enough to earn him the show’s top prize.

In south Indian kitchens, tiffin is not a leisurely production. The term “all-day breakfast" here caters to a hunger very different from humanity’s perpetual craving for pancakes, golden hash browns and three kinds of eggs. Here, upma can seem like an amuse-bouche. Usually, consistency is the first and least negotiable feature of the south Indian breakfast: Your parents’ idli and dosa, at least in memory, will always taste the same, and you will always be able to quantify your longing for it (you eat three idlis with molaga podi; your father eats four with coconut chutney). These breakfasts are created in prose. But the upma is a small, unpredictable piece of poetry. Not a romantic one, of course; maybe a delightful limerick.

Like peanut butter, it can be chunky or smooth. At Mysore Café (this newspaper’s favourite lunch spot in Mumbai), Madras’ old rival, it is served on the principle that deliciousness is directly proportional to cashew nuts. At home, you can even apply upma-principles to vermicelli, beaten rice and broken wheat, to make semia, avil (poha) and lapsi upma. Indigo Deli and Café Basilico, in a Maghrebi mash-up, even produce a delightful version made with couscous.

You can eat it when you are fasting, according to most Hindu notions of the fast; it is nourishing, but modest—except cashew nuts. It accommodates most non-starchy vegetables with grace and poise. Its most basic flavour comes from ginger, curry leaves and mustard seeds. Its key quality, however, is texture. Too much water makes it a grainy broth; too little can make it seem like a mud cake with fried onions.

But its protean quality is what makes it all things to all people. Its versatility takes the upma’s virtues beyond its austere origins.

It isn’t just comfort food; if that were all, it would have a harder time crossing the gourmet line. If that were all, it would be melancholy to share it with a friend to whom I was saying goodbye. Comfort food is khichdi. The upma is for joy.