A friend in Washington DC recently told me that the one dish most associated with the US capital was something called a half-smoke. I was stunned. I’d lived on the East Coast for more than a decade and had eaten far and wide, but I’d never heard of such a thing.

Apparently I was in pretty good company. When US President Barack Obama visited the Washington DC institution Ben’s Chili Bowl shortly before his inauguration in 2009, he reportedly asked, “What’s a half-smoke?” He was promptly served one and now knows, or at least thinks he does. So does former French president Nicolas Sarkozy, who made his own pilgrimage to Ben’s.

Yes, Baltimore has crab cakes. New York City has pastrami. Chicago has deep-dish pizza. And Washington DC – it turns out – has half-smokes.

The thing is, a little research revealed that no one is exactly sure who made the first half-smoke, or what, exactly, a half-smoke should be. This sausage on a bun is sometimes covered in chili, sometimes topped with cheese or diced onions, and sometimes doused with mustard. It’s most associated with Weenie Beenie (2680 South Shirlington Rd, 703-671-6661), which started slinging half-smokes in 1954 in nearby Arlington, Virginia, and Ben’s Chili Bowl, which opened in 1958.

A few days after chatting with my friend, I was in Washington DC, sitting at a table at Red Apron, a small chain of butcher shops with in-house eateries. With me were food writer Nevin Martell and Nate Anda, head butcher at Red Apron.

“It’s only been recently that chefs have embraced the half-smoke,” Martell said. “Only in the last few years have local chefs decided to put a half-smoke on the menu.”

Why and how the half-smoke suddenly became the DC food is as much a mystery as the sausage itself. “It’s a mythical sausage,” Anda said. “No one even knows what the ‘half’ is in the name.”

Perhaps the sausage got its name because it’s often half beef and half pork. Or it could be because some restaurants cut a slit down the top, nearly slicing it in half. The “smoke” could come from the fact that the sausage is smoked before it’s grilled.

As Martell noted, the mystery doesn’t stop at the name: “No one can agree what goes in a proper half-smoke. Is it topped with chili? If so, what’s in the chili? Is the ratio of meat half beef, half pork? Should you put cheese on it? What kind of spices should you use?” (Obama reportedly asked for cheese to be added, calling out, “not the Velveeta” kind.)

“The problem,” Anda said, “is that Ben’s and Weenie Beenie, which everyone looks to as the standard of the half-smoke, have never revealed their recipes. As a result chefs have interpreted the half-smoke their own way.”

Just then a server set a rectangular cutting board on our table. On it were sausage slices stacked alongside a small bowl of mustard. This was Red Apron’s interpretation, created by Anda. On one side was his partly smoked and grilled version and on the other, quite uniquely, a smoked and pickled version. I picked up a slice of grilled sausage and popped it in my mouth. Red Apron does a 50-50 split between pork and beef with a 75-25 split between meat and fat. I bit down and found the meat unctuous with a bit of spice lingering on my palate. There was also a slight undertone of dark porter beer, which Red Apron uses in the emulsion process. It was good. I liked it. But then I tried the pickled version.

It was like nothing I’d ever tasted. This paler sausage was complex and extremely flavourful. I could detect aspects of apple cider vinegar, an essence of sugar and a tingle of cayenne, all of which Red Apron uses in the mixing process. It reminded me of a dish you’d find in Vietnam, a country whose culinary tradition often captures sweet, savoury, sour and spicy all at once. Red Apron’s pickled half-smoke did all this in one sausage.

Martell and I bid farewell to Anda and headed to Churchkey, a restaurant in the Logan Circle neighbourhood that serves elevated comfort food. Bearded and inked-up chef Kyle Bailey brought out his half-smoke, a blend of 60% pork and 40% beef, on a homemade poppy-seed bun. The sausage was stuffed with cumin, mustard powder, minced garlic and then smoked and grilled.

But yet again, there was no chili served on top. “I hate chili,” said Bailey. “I just don’t like it and I’d never put it on anything.” He laughed and added, “Chefs are often at their best when they’re interpreting and that’s what I’ve done here.” He reminded me of the half-smoke’s nebulous definition. Whatever the case, Bailey’s version was very good. Most importantly, the casing had a nice snap to it, one of the chief characteristics of a good half-smoke.

But I yearned for something more traditional. And by that, of course, I meant Ben’s Chili Bowl. Ben’s does hot dogs and hamburgers, but most people come for the half-smokes. Anyone who has lived in Washington DC for at least a year has ended up at Ben’s after a night out of drinking and concert going. It just happens.

“This is the iconic half-smoke,” Martell said, giving a swan-like sweep of his arm as he gestured to the sausage. “But I call this tourist food because there’s nothing in here that’s made on the premises. Even the sausage, ironically, is made in Baltimore.”

I stared down the half-smoke noting it was slathered in bean-less chili and was sprinkled with onions. After the first bite, I realized how underwhelming it was. It had neither the nuances of Anda’s half-smoke nor the taut snap of Bailey’s. It was like a thick hot dog with bland chili on it.

Disappointed, Martell said he had one more place for us to go. We stopped into DCity Smokehouse, a diminutive barbecue spot in the Bloomingdale neighbourhood. The half-smoke here was a delicious mess: a five-inch sausage cradled in a soft plain bun. What really made this half-smoke stand out was the liberal dousing of smoky brisket chili. Mustard and raw onions were added.

There was a snap to the sausage and a tingle of spice lingered on the tongue. “This is what a half-smoke should be,” Martell said between bites. It was really the supporting actors – the toppings  – that made this the best half-smoke I’d eaten that day. “The brisket chili brings it all together,” said Martell. “It makes it a complete dish. This half-smoke is everything that Ben’s is pretending to be.”

Martell and I left and walked through the neighbourhood, block after block, chatting about music. After we fell silent for a few minutes, he looked over at me: “I can’t stop thinking about that last half-smoke.”

“Me too,” I said, wishing I had room for another.

After eating four different half-smokes in a matter of two hours, I was decidedly smoked out. But with the DCity Smokehouse half-smoke still lingering on my taste buds, I could walk into the Washington evening satisfied that I’d eaten some of the best examples of this iconic dish.