I went to Edinburgh on the promise of some of Britain’s best bagels. That’s a notion bound to cause ructions, because almost everything about the humble bagel is contentious. For a start, I’m possibly spelling it wrong. “Stop Americanising beigel!” you may be harrumphing, pronouncing that “ei” as in “Einstein”. Likewise, if you’re a fan of those soft, yielding, handily freezable bagels available in multipacks from supermarkets, many will kvetch that those are merely ring-shaped imposters. Soft? Yielding? Pghhh.

A good bagel, some believe, should be an arduous task. The dough must be boiled before baking, in a bid to create a genre of jaw-taxing chewiness that requires a midpoint recovery interval at the four-bites-of-salt-beef-or-chopped-herring stage. One definite is that, historically, good bagels have been found on Brick Lane in the East End of London. However, which shop there – either Beigel Bake or Beigel Shop next door – can call itself the real deal, well, that’s the start of an entirely new bun-fight.

The Edinburgh-based chef Tom Kitchin confounded matters more late last year by acquainting me with the work of the Canadian-Jewish bagel bakery owner Larah Bross. Her bagels are 100% organic, pre-boiled in honeywater and baked on longboards wrapped in hessian. The dough is Montreal-style, containing eggs, which makes them softer than a Brick Lane bagel. They taste better, too. There, I’ve said it.

Facebook Twitter Pinterest Bross Bagels’ Leither: ‘Filled with chilli-wafted salmon, jalapeño cream cheese, bread-and-butter pickles and a lot of cracked black pepper.’

Bross Bagels, which now has branches in Leith, Portobello and on Queensferry Street in the Scottish capital, has enjoyed a breathless momentum over the past two years. It’s the sort of infectious happiness that only unabashed carbohydrates stuffed with good stuff such as melted applewood cheese, chicken schnitzel or jalapeño cream cheese can provide. We went to Edinburgh to investigate Michelin-star, high-concept, budget-obliterating joints. Funnily enough, weeks later, it was the hour we passed, mid-morning, upstairs at Bross Bagels’ Leith branch, in its gloriously sparse eating area, upstairs from the hectic, fragrant bakery, that stuck in our minds as the most perfect.

Larah Bross’s take on what is permissible as bagel filling will, of course, cause further brouhaha. Indeed, there’s salt beef, pastrami and lox, naturally, with all manner of recognisable bedfellows: dill pickles, red onion, sauerkraut, Russian dressing and crisp capers. But the true beauty of Bross Bagels is how it dances a dainty line between timeworn kosher flavours and tangents of brash, delicious modernity. No one will go hungry here.

Facebook Twitter Pinterest Bross Bagels’ chicken parm: ‘A riff on Middlesbrough’s kicking-out-time classic.’

The Buffanono, for example, is a flurry of deep-fried cauliflower with melted Monterey Jack cheese, buffalo sauce and Mama Bross’s ranch dressing recipe. Or there’s a vegan reuben salt-beef pastiche made with jackfruit, or vegan kimchi sauce to liven up your “Holy Heebster” avo-and-eggs breakfast bagel. And you can shove a hot, fresh latke in anything for an extra £1.

I love how Bross Bagels bungs all of these things on its menu with equal billing, and how it calls its bacon bagel “The Goy” and offers “Facon” fake streaky bacon for folk who kind of want to eat swine but also don’t do swine. I also love how there’s a section on the menu called “Fussy Pants”, for any diner who wants anything as abstemious as “a fried egg”.

Bross Bagels is a whirlwind of perfectly judged brashness and thoughtful, come-one-come-all affability. Upstairs may be just a bunch of benches, with a small sink to wash your hands in and a few rolls of kitchen paper to wipe your face on, but on a Saturday morning, there are dogs, babies, joggers, vloggers and still-drunk-and-going-home nightshifters, all eating in harmony.

Facebook Twitter Pinterest Super-size Leith-style: add a hot, fresh latke for an extra quid.

Two bagels were especially noteworthy: the chicken parm is a riff on Middlesbrough’s kicking-out-time classic, the “parmo”: a northern English culinary sensation of breaded chicken escalope with cheese that’s best eaten standing up at 2am in a taxi queue wearing a Lipsy frock.

The Bross Bagels parm contains schnitzel, melted mozzarella, jalapeños, and Larah’s Uncle Jimmy’s special meshugga marinara sauce: “famous three-day-hangover cure,” it claims on the menu. The parm is a sloppy yet crisp, sweet but slightly hot, honking slab of premium-grade junk food. The “Leither”, meanwhile, is filled with chilli-wafted salmon and jalapeño cream cheese, a scattering of bread-and-butter pickles and a lot of cracked black pepper. The gang down at Beigel Shop in Brick Lane have been serving some of Britain’s greatest bagels since 1855. They didn’t see Larah Bross coming.

• Bross Bagels 105 Leith Walk, Leith, Edinburgh EH6, 0131-629 4560. Open Mon-Fri 8.30am-3.30pm, Sat & Sun, 9am-4pm. About £9 a head, plus drinks and service.

Food 8/10

Atmosphere 8/10

Service 8/10