Chop Chop, 248 Morrison Street, Edinburgh EH3 8DT (0131 221 1155). Meal for two, including drinks and service: £30-50.

At a time of great political uncertainty it’s natural that we should search for the things that unify rather than divide us. There are the obvious markers, like our desires: for safety and warmth, for belonging and the type of sex that doesn’t make us cringe when we recall it. There’s language in general, and inventive expletives in particular, and a ravenous hunger for products made by Apple. Then again, there’s also Samsung. So that doesn’t get us very far, does it?

The one item that defines and unifies us is the dumpling

In truth, none of these really gets to the true essence of what it is to be human. They’re too vague, too variable, too messy. But don’t worry. I’ve done the heavy lifting. After a lifetime’s research and a single night out in Edinburgh, I am ready to nominate the one item that defines and unifies us: it’s the dumpling.

Stay with me here. The dumpling is present in every culture. The Poles have their pierogi and the Russians, their pelmeni. Both nationalities will insist theirs are entirely different even though they look strikingly similar. It’s their culture; we can’t get involved. The Chinese have wonton, the Japanese have gyoza and the Italians, being the Italians, have at least one for every former city-state, from ravioli to agnolotti to tortellini and beyond. Perhaps there’s a human migration map that explains this – a global dumpling trail which sees the notion handed from tribe to tribe across the world.

Or perhaps they are just so useful that for each culinary culture not to have developed one independently would be ludicrous. First, they are a brilliant way to use up scraps of food that might otherwise be wasted. The filling of a dumpling does not have be made from the vegetable’s heart or the animal’s prime fillet, but from the bits left behind. Second, the doughy packaging makes them easy to cook. Third, you can count them out so everybody gets an equal share, thus avoiding arguments. And, finally, they are extremely comforting. While you are eating dumplings nothing bad can happen.

The art of crimping: chilli chicken guo tie dumplings. Photograph: Robert Perry/The Observer

When Jian Wang arrived in Edinburgh in 1997 from equally chilly Dongbei in northeastern China, she found a city which she felt had a dumpling deficit. (Of course the Scots have long had a tradition from the solid suet branch of the dumpling family tree, but that’s a different matter altogether; it’s driven by poverty and the need to get cheap carbs into the diet.)

Wang set up a company to manufacture the dumplings she knew from home, which has gone on to supply wholesalers and restaurants all over the UK. In time it sprouted its own restaurant, the venerable Chop Chop on Morrison Street (followed by another in Leith). If, like me, you adore dumplings, you have to go. Times have been tough for the company recently, with the closure of a short-lived venture in Glasgow. That’s all the more reason for celebrating what the original in Edinburgh has been doing so well since 2006.

It’s a big, square, high-ceilinged room, painted the obligatory shade of imperial red; a place to sit elbow-to-elbow and thigh-to-thigh. There are two basic dumpling types: the small jiao zi, made with translucent skins, which are boiled, and the larger, denser, guo tie with their pleated edge, which are fried to crisp on one side. Portions are both large and generously priced: £9.20 gets you either 16 of the jiao zi or eight of the guo tie; £4.85 gets you half that. On the table are bottles of soy and of a deep dark Chinese vinegar with that familiar sweet caramel end. There’s also a serious bit of chilli oil, full of crunch and fire. Into a bowl goes equal amounts of all three. Your dipping sauce is done.

Standout dish: jiao zi dumplings filled with lamb and cumin. Photograph: Robert Perry/The Observer

If there is a standout from the dishes we try, it is the jiao zi filled with that classic northern Chinese mix of lamb and cumin, the gossamer skins breaking to release gusts of meatiness with just a hint of lanolin and the aromatics of the roasted spice. They’re so good we order another bowlful, chasing the slippery little blighters around the glazed bowl with our chop sticks.

By comparison pork and coriander jiao zi are almost delicate, the filling lifted to the realms of the special by the liberal application of sesame oil, ginger and garlic. Chilli chicken guo tie are all about the crunch of the fried shell, and the slap of heat at the end. It is a cliché to talk of certain food items as being addictive. I could probably kick the habit. I’m just not sure I want to. These are utterly compelling. There is, it seems, always room for just one more dumpling.

The rest of the menu, which hinges between a familiar form of British Cantonese cooking and something more northern Chinese and fiery, is variable. This is salty, garlicky food. If you come for dinner, put a glass of water by your bed overnight. Expect to refill it a couple of times before dawn. Sliced lamb with more cumin has a disappointing boiled quality, as though it has left the best of itself behind in the pan. A dish advertised as crispy northern sweet and sour chicken promises a punchier version of the old Anglo classic, but it’s just as cloying. It’s also as orange and unattractive as a sociopathic man-child US president.

Shatters between the teeth: battered squid. Photograph: Robert Perry/The Observer

Far better is a dish of extremely crisp battered squid which seems to crack and shatter between the teeth. A boisterous plate of shredded pork with coriander is as much sliced ginger as it is meat, delivering crunch and succulence in equal measure, all overlaid by the waft from the bunches of fresh herbs. Spinach comes doused in earthy soy, with peanuts and garlic; green beans are dry fried with fresh chilli. These dishes make us feel like we are being good to ourselves, even though they leave me certain that I will wake in the night with my dry tongue glued to the roof of my mouth.

For dessert they offer a deep-fried dumpling, but we decline

For dessert they attempt to play to their strengths by offering a deep-fried dumpling, but we decline, for fear it could sully the memory of the savoury version. The deep-fat fryer is not always the answer, even in Edinburgh. This is seriously comforting food at a very good price. We work very hard to spend £25 a head. Which isn’t a lot of money for an eating experience that somehow manages to remind us of all that we, as humans, have in common.

Jay’s news bites

The venerable Saigon Saigon in Edinburgh is frequented by the local Chinese community looking for food from the less refined end of the tradition. Despite the name referencing Vietnam, there’s both a serious Cantonese dim sum menu and a wide selection of rough and ready Sichuan and Hunanese dishes, piled with enough fresh chillies to keep the cold winds off (saigonsaigon.co.uk).

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A global review of how 99 foodservice brands deal with animal welfare issues has placed Domino’s and JD Wetherspoon at the bottom of the heap of the 28 in the UK that were studied, for showing ‘no evidence’ that animal welfare was part of their agenda. Highest ranked were McDonald’s and Greggs.

Email Jay at jay.rayner@observer.co.uk or follow him on Twitter @jayrayner1