Story By Brian Hernandez | Photos by Caren Hanten / Timeless Photography

In 2020, while the world slowed down, Sean Dempsey, owner of Dempsey’s Brew + Pub & Restaurant and Danger Von Dempsey’s Pizzeria & Brewhaus, was gearing up. Watertown, South Dakota became the unlikely launchpad for a side hustle that would soon become a cult favorite: Dempsey’s Proper Hot Dog Co. Amid pandemic chaos, restaurant restrictions and supply chain headaches, he launched a different kind of foodservice venture—one with wheels, buns and a whole lot of mustard. After all, he says, “People really love a good hot dog.”

In other words, wieners are winners for this well-known pizzaiolo and member of PMQ’s U.S. Pizza Team.

Dempsey grew up steeped in restaurant life and became the heir of a culinary empire founded by his parents, Lyne and Bill Dempsey III. The original Dempsey’s restaurant opened in 1999 and quickly became a local legend. Sean Dempsey officially took the reins in 2015, adding several Danger von Dempsey’s stores along the way.

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Bill briefly retired in 2016 but couldn’t stay out of the game for long. Suddenly obsessed with hot dogs, he went on a quest to find the best one in the land. “He ordered every hot dog he could online…and eventually landed on Vienna Beef from Chicago [for the meat],” Dempsey recalls. 

Bill started his hot dog cart in March 2020 before retiring again. The cart rotated down to his son like a perfectly steamed wiener on a carousel. Sean decided to expand the offerings to include five or six different styles of dogs, along with a Hot Dog of the Week, which often mirrored the Pizza of the Week at his pizzeria. It blew up. “Thankfully, my staff was supportive enough to dub me the ‘Hot Dog King of South Dakota,’” Dempsey says. “Please don’t tell your friends.”

A Summer Moneymaker
Why a hot dog cart? They’re efficient, affordable and a crowd favorite. “They have a huge advantage versus mobile food options,” Dempsey says. “We picked up a solid one for under $3,500. It’s also something in our market that just didn’t exist. It’s mobile. You can pull it like a small trailer….There are different models for carts, based on volume. For us, we went with a mid-size model, something that can handle a lot, but not to the point of needing a whole food truck.”

Once on site, setup takes less than 10 minutes. “We have two people: one person to run the mobile POS and one to make the dogs. In a rush, it’s easy for the ‘front’ person to help sling dogs as needed. We also run only three-hour shifts, for the most part, so we get out, set up, cook, and break down pretty fast.”

The carts operate three or four days a week, mostly during the summer, and return home every night for cleaning and prep. Best of all? They clear $60,000 in three months, Dempsey says.

Burn and Turn
Dempsey also uses the cart to test potential new markets for his pizzerias. Without even realizing it at first, he was able to gather valuable intel—foot-traffic patterns, customer preferences and neighborhood dynamics—long before committing to a particular market.

“When we open a new shop, we announce we’re coming to town X,” Dempsey notes. “We move a hot dog cart out into the new market and start teasing what we’re going to do at the store. It works pretty well. We make some bucks, and we get a lot of press. Though, in our case, we have to let them know the pizzeria won’t be selling hot dogs—[they’re offered] only in the summer and only on the cart.”

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Dempsey’s Proper Hot Dog Co. offers a virtual U.S. road trip on a bun. “Our biggest sellers are based on hot dogs around the country,” he says. “The Cincinnati Dog (chili, cheese and Fritos); a Seattle Dog (sauteed peppers, onions and cheddar sauce); the Warsaw (sauerkraut, stone-ground mustard and caramelized onions); the O’Malley (corned beef, Thousand Island and sauerkraut); and a Chicago Dog. If you don’t know what that is, we can’t be friends.”

Dempsey’s not ruling out a brick-and-mortar hot dog restaurant, either. “I think a two-person staff, with a small selection of craft brews and a menu of six to eight dogs in a 20-seater, would crush it. Try and stay true to the nature of the hot dog cart—burn and turn.” His inspiration? “Dirty Frank’s Hot Dog Palace in Columbus, Ohio!” he says. “That place rocks….They have fun with it. [You’d need] a solid sense of humor to cater to that crowd. But Late-Night Dogs, Dogs After Dark, Nooners—it would be a riot.”

Sean Dempsey: pizzaiolo, brewmaster and, now, hot dog czar. Proof that the side hustle, when done right, can feed more than your bottom line—it can fuel your passion. So if you find yourself in Watertown this summer, odds are the Hot Dog King will be there, tongs in hand, doing it proper.

Brian Hernandez is PMQ’s associate editor and director of the U.S. Pizza Team.

Food & Ingredients