A perpetual line snakes out the door at Little Big Burger, the Pearl District’s first independent fast-food joint, a mere napkin’s pitch from Powell’s City of Books. Suits and dudes, off-duty baristas, Twitter-happy restaurant hunters, even a few hummus-loving yogis, mats in hand, have come looking for instant bliss on a bun. The burgers here sizzle so fast and furious on the open grill that the hiss threatens to drown out the crowd as Michael Jackson shrieks in the background.

The mood in this reimagined soda fountain is at once sterile and familiar but pulsing with personality—Lego-red hues, blond wood and slate walls, mind-bending murals, the kitsch and pop of Asian cool. If Ray Kroc went to the Rhode Island School of Design, with a semester in Tokyo, history may have looked like this. As noon approaches, the energy keeps surging. By the time the sound system blasts Queen’s foot-stamping “We Will Rock You,” a threat emerges: will customers start a wave?

Behind the counter, 32-year-old impresario Micah Camden—the notoriously loose-lipped kingpin of the Killingsworth restaurant oasis that includes Yakuza Lounge, Beast, and D.O.C.—shouts to be heard. “Watch that! Truffle fries coming!” he yells to a T-shirt-clad line cook as he hands customers his newfound gold: foil-wrapped natural beef patties, no bigger than your palm, but commanding lines and blog buzz since opening day in September. Whispers Camden loudly to a friend: “Eleven days open and we’re already at $35,000. Can you believe it?”

That’s a lot of patties and buns. Indeed, Little Big Burger could be the Burgerville for a new generation: fast and fun, eco-minded, and feeding a demand for genuine food on the cheap. Plus, there’s beer—nearly two dozen canned brands stacked on shelves as though posing for a Warhol painting. The menu includes a quarter-pounder, ?made to order for a wallet-friendly $3.25, served with a picnic mentality—no dishes or trays, just make-your-own plates out of brown takeout bags.

In one swoop, Camden and partner Katie Poppe caught the triple zeitgeist of food carts, the artisanal cooking fixation, and the burger craze. Spinning off Little Big’s overnight success, Camden and Poppe already have two more branches in the works for 2011, at NE 30th Avenue and Killingsworth Street (in Camden’s recently closed Fats) and in the West Hills.

Within the vast fast-food landscape, Camden detoured away from the extensive, all-American options found in mega-chains and the region’s beloved Burgerville. Little Big Burger, instead, takes its cues from West Coast cult chain In-N-Out Burger, limiting choices to four items: burger, cheeseburger, veggie burger, and fries. Everything is made out in the open; nothing shrivels under a heat lamp or confronts a microwave—also In-N-Out signatures.

Of course, In-N-Out became a California pop-culture phenom, complete with a “secret menu” (a world of insider custom orders, like “animal style” with mustard fried into the patties) and love from the likes of SpongeBob Squarepants and Fast Food Nation muckraker Eric Schlosser. The Dude’s crew in The Big Lebowski eats at In-N-Out. It doesn’t get cooler than that.

Little Big Burger may not be ready for a big-screen close-up, but its early performances, flavorwise, are already outshining its elders. Yes, the truffle fries are frozen Washington Yukon golds, not handcut fresh like In-N-Out’s. They might not knock over Burgerville’s seasonal wonder, the sweet-potato fries. But they’re pretty terrific and a steal at $2.75: crispy outside, creamy-starchy within, elevated by sea salt and homemade ketchup. The scent of truffle oil is just right—a hint, a seduction, not the usual snort of overkill.

The hand-formed burgers, more tall than wide, disappear in five or six bites, just enough time to deliver some beefy perfume and lip-smacking crunch. I like the compact size (guys will want two) but mostly the craft. Brushed with browned butter before hitting the grill, the locally baked brioche buns gain just a touch of nutty flavor. Fixin’s include organic shaved red onions, lettuce, and pickles from local heroes Pickleopolis.

 The choice of four local cheeses is noble, but a fatter slice of Tillamook cheddar would be even better, and a sharper, gutsier Oregon Blue. (Go for the Rogue chevre: the hot, creamy cheese transforms the whole production into a rich, delicious mess.) Aioli, the one “secret” element available by request, could land a more decisive garlic punch. Overall, Camden is playing it a little too safe right now. To jump to the burger big leagues, he needs something weirdly delicious and addictive. And to succeed on any level, consistency will be key. On a recent evening, a request for a medium-rare burger turned up something red seemingly straight from the fridge. (No worries, the accommodating cook assured me, remaking the order and confiding, “We use the same stuff for steak tartare at Yakuza.”)

The mastermind behind four restaurants in Northeast, Camden knows good food. The restaurant–cum–dinner ?party Beast was his most brilliant move, conceived as a showcase for now star chef Naomi Pomeroy (who eventually bought him out). But quality has see-sawed at Yakuza and D.O.C., as he’s churned through chefs. With Little Big Burger, Camden’s played to his talents as a designer and idea man, and set out to blaze the next new culinary trail: fast food done right.