The burger: It's road trip season, and last weekend I decided to take the long route to Madison (emphasis on looooong) and go by way of Prairie du Chien, for one reason: Lunch at Pete's Hamburgers.

It was my third or maybe fourth visit to Pete's since I first encountered this must-visit burger destination about a dozen years ago. This time around, I must have hit some kind of scheduling sweet spot, because I lucked upon a first: No line. True to past experience, however, I watched one quickly form as I stood and scarfed down my (extraordinary, truly) burger. And then, piggishly, a second one.

As Wisconsin's second-oldest settlement, Prairie du Chien is steeped in history. For example, tourists finding themselves in this old Mississippi River town should find the time to tour Villa Louis, a stunning Victorian estate with a remarkable Italian Villa-style mansion with a Minneapolis connection: it was designed by E. Townsend Mix, the Milwaukee architect also responsible for the late, lamented Metropolitan Building.

Although Pete's isn't affiliated with the Wisconsin Historical Society, it does own a fascinating and beloved chunk of Prairie du Chien's past.

The business dates to 1906, when Pete Gokey, a painter and paint store owner, pitched in and made burgers for a volunteer fire department fundraiser at a popular saloon. He was frying burgers in cast iron skillets when he hit upon an ah-ha moment: he discovered he could keep the patties from growing dry by adding water and onions to the pan.

Gokey had a hit on his hands, and he parlayed that methodology into a side business that eventually grew into Pete's. Three generations later, Pete Gokey's pride and joy is still going strong.

There's a fascinating ritual to Pete's. Well, engrossing to someone like me who is obsessed with the way restaurants operate.

Technically, Pete's isn't a restaurant, it's a stand, tucked into a sliver of an empty lot on Prairie du Chien's charming main street. A trailer, really. One that dates to the 1940s. And yes, Pete designed and built it. He died in 1972, after operating his namesake for 63 consecutive years.

Like their illustrious ancestor, Pete's descendants cannily combine the burger business with show business. The cooking takes place in the trailer's front end, a cramped workspace surrounded on three sides by windows. It's quite a performance – if the Chamber of Commerce isn't marketing Pete's as Prairie du Chien's own summer theater festival, it should – and one that's not to be missed.

The Pete's burger is still prepared, Pete Gokey-style, flying in the face of established burger-making tradition. Each one starts as a baseball-sized meatball (it's straight-up ground beef), laid out in orderly rows, one next to another, across an aluminum foil-lined flattop filled with what looks like about an inch of simmering, steaming water that's covered in thinly sliced, slow-cooking onions.

The patties are prepared in batches. Huge batches.

"I've just put 50 on," said the friendly woman working the griddle. "But on Saturdays when it gets really busy, the guys can get 70 of them on here at a time."

As they cook, each meatball is shmushed with a spatula into a thick patty. They're flipped, sprinkled with a little salt and simmered through to a no-nonsense medium. That's it.

The results are astoundingly delicious, despite the decided lack of charred, caramelized beef. As you'd expect, the taste of onions dominates, in a very good way. This is one of those burgers where patty and bun fuse together, making for an honest-to-goodness mouth-melting experience.

The exceptional buns are sturdy enough to carry the weight of that outrageously juicy, plus-size patty, but it radiates a tender -- and I'm assuming dairy-boosted -- bite. They're baked fresh, daily, at nearby Huckleberry's.

The ascetic toppings selection could have come straight from a Trappist monastery. Forget about cheese, lettuce, tomatoes, pickles or mayonnaise, and don't even think about bacon, fried eggs, avocados or any other chichi embellishment.

Nope, you'll be asked a simple question: "Onions, or no onions?" (My suggestion: the former, and your patty will be topped by a small pile of soft, slippery, translucent and teasingly sweet simmered onions) and then the server will turn your attention to the condiment portion of the transaction. Would you prefer ketchup, a caution sign-colored mustard or a more coarse, stone-ground mustard? Make your choice, and they'll do the rest.

My usual Madison routine has me testing the outer limits of the speed limit on a fairly dull four-hour drive on I-94. Last weekend's itinerary, the bulk of which took me along Wisconsin's stupendously scenic, Mississippi River-hugging Hwy. 35, lasted just under seven hours, including my Pete's pit-stop. Was it worth the extra time? Absolutely. My one regret? That I couldn't hang around for dinner.

Price: $4.25.

Fries: None. A bag of potato chips is $1.

Adddress book: 118 W. Blackhawk Av., Prairie du Chien, Wis. Open 11 a.m. to 9 p.m. Friday and Saturday, 11 a.m. to 7 p.m. Sunday.

Talk to me: Do you have a favorite burger? Share the details at rick.nelson@startribune.com.