Walk through the Altstadt in Salzburg on any given evening and you'll smell it before you see it. Fried onions, curry, pork fat hitting a hot grill. That's a Bosna stand. The queue will be long. Nobody minds. You stand there with your hands in your pockets and wait because the thing at the end of that line is worth it.

A Bosna is two thin Bratwürstel grilled until the casings blister and split, then tucked side by side into a Weißbrotgebäck, a white bread roll that's been sliced open lengthwise but not all the way through. Fried onions go on top. Then a stripe of mustard, a dusting of curry powder, and chopped parsley if the stand owner is feeling generous. Some places have their own Gewürzmischung, a spice mix they've been tinkering with for decades. They'll never tell you what's in it. You learn to stop asking.

I eat Bosna the way everyone in Salzburg eats Bosna: standing up, outside, usually in weather that doesn't entirely cooperate. You hold the roll with both hands because the onions will slide and the mustard will find your sleeve if you get careless. It's not elegant food. It's not trying to be. It's the thing you eat after a long day at the Grünmarkt or walking through the Mirabell gardens, and it tastes better standing in the cold than most things taste sitting down in a warm restaurant.

Gretel always said that simple food done well is harder to pull off than complicated food done adequately. The Bosna proves her right. There are four components. Every one of them has to be good.