Mark Reitman, a teddy bear of a man wearing a white lab coat, a yellow hardhat, and a smile broader than a jumbo Polish sausage, stands in front of a swinging metal door at Vienna Beef’s North Side headquarters. “So, you’ve seen the movie Willy Wonka and the Chocolate Factory?” he asks. “Well, this is called Mark and the Wiener Factory.”

It’s 8 a.m. on a Monday in July, and school is in session for me and two fellow freshmen in frankfurters who, like hundreds of aspiring sausage slingers before us, have enrolled in Vienna’s esteemed Hot Dog University. In this intensive two-day Art of the Cart course, we’re learning how to peddle Chicago’s most iconic street food. The first order of business: a tour of the Vienna plant. Before we enter, Reitman has another question. “If you should fall into a grinder, there’s just one thing I need to know: Do you want to be turned into a natural-casing or a skinless hot dog?”

Reitman, 67, is a wisecracking former school counselor and natural-born salesman who transformed into a PHD (professor of hot dogs) after three successful years running a cart outside a Wisconsin outlet mall. He’s perhaps the only man in America who can spend a good half hour explaining how to garnish a Chicago hot dog. (Dress the dog, not the bun. Yellow mustard always comes first. Then atomic-green relish, chopped onion, tomato wedges, pickle spear, sport peppers, and a dash of celery salt—in that order. No exceptions.)

In 2006, Reitman started Hot Dog U in Milwaukee. In 2009, he approached Vienna about bringing his curriculum in-house. The company bit, and more than 750 students have walked these hallowed halls since. His placement rates are impressive: 50 percent of graduates start businesses, and 75 percent of those are still running today, he says.

We wander into the buzzing 150,000-square-foot production facility, where an astounding 104 million sausages were made last year. Forklifts putter along as we proceed past the boning room (insert wiener factory joke here). A dozen men slice fat from beef briskets, tossing the trimmings onto a conveyor belt moving toward a grinder. (For the record, not a cow hoof or rectum is in sight.)

Today, my classmates are Scott Corrie, a 48-year-old opening a stand in downstate Watseka, and John Holly, 32, a fireman and former Navy Reserve corpsman from Bridgeport, who wants to launch a cart business that employs fellow veterans. I’m here to burnish my own grill sergeant status with insider tips—and enjoy the kind of unfettered access to encased meats that even for $699 in tuition feels like a bargain.

After the tour, we convene in Reitman’s office for Hot Dogology 101. Holly raises his hand and asks whether you need to sell natural-casing franks or if the cheaper skinless ones will suffice.

“You can only get away with skinless in Wisconsin, or south of Chicago,” Reitman says. “There is something beautiful about snapping into a natural-casing hot dog.”

Jumbos are a different story. Reitman explains that casings made from delicate sheep intestine can rein in smaller sausages, but larger links require thicker hog ones to hold the meat together. “It’s like biting into a rubber band,” he says. His advice: Go skinless when you go big. Then he imparts the secret to replicating that signature snap. Score the ends, cut a few slits on the sides, and toss it on the grill, where the heat “causes the protein shell to harden up.”

Out of nowhere, Reitman drops a bomb: “So, do any of you put ketchup on a hot dog?” My classmates and I look at each other nervously. Is this a trick question? “Here’s my feeling,” he continues. “I don’t give a rat’s ass what you put on a hot dog, as long as you keep buying them from me.”

His most eye-opening advice involves marketing: “You’re not selling a hot dog. You’re selling an experience.” That means decorating the cart in bright colors, playing upbeat music, and griddling fragrant onions. “You don’t hawk customers,” he explains. “You let them come to you.”

A few weeks later, I test my new skills in the real world. I contact Marci Lehnert, owner of Hubby’s in the Dog House and alum of Hot Dog U (class of ’09). While many people who take Reitman’s course are retirement-age folks following their dreams, Marci and her husband, Will, are in their 30s. “We were both corporate, midlevel nobodies, so we took $10,000, bought a permit and a cart, and dove in,” says Marci.

The Lehnerts hit all the right customer-enticing notes: As I approach Oz Park, I smell grilled onions. From 50 yards away, I see the cart’s red-and-yellow umbrella and hear the feel-good sounds of Steely Dan. Our professor would be proud.

After a tour of the operation, Will puts me to work. The multisensory attack soon lures a couple of 60ish ladies, who order two lemonades and two hot dogs. I fumble around the bins and use tongs to grab a slippery sausage from its warm bath and place it on a bun like a pro.

“We already ate lunch, but these smelled so good we had to get one,” says one of the women as she helps herself to condiments. (Reitman recommends letting customers dress their own dogs so they don’t hold up traffic—or complain.)

Breaking from Reitman’s keep-it-simple philosophy, Hubby’s also sells vegan dogs and offers fussier condiments, such as barbecue sauce and cheese. But when a lanky teenager orders the Buffalo blue cheese topping, Will discovers he’s forgotten the crumbles at home. I improvise and offer the kid a “heart stopper” piled with extra bacon. The concoction is a hit, and soon the rest of his buddies line up. Will sees it all the time: All it takes is one customer to spark a crowd. “The jealousy factor kicks in,” he says.

Toward the end of my shift, a nine-year-old in a white polo shirt walks up, counting his change, and orders a Polish. I carefully score the ends and throw it on the grill to give it the simulated snap. As Reitman taught me, I lovingly turn it to even out the char marks. In my mind, I’m helping the youngster hone his appreciation for Chicago’s quality meat products, serving a memory that he’ll never forget.

But the kid doesn’t care. I can barely look him in the eye as he destroys the thing by drowning it in ketchup. Then I remember Reitman’s words and think, Doesn’t matter—he’ll be back.

Or maybe he’s from Wisconsin and just doesn’t know any better.