It's just before 7 a.m. on Sunday morning, and Erik Jensen has been working for hours, already on his second day of vacation from his graphic-design job.

Tall with dark, tousled hair and blue eyes that become sharp with concentration, Jensen attempts the classic "rosetta," an intricate design made of foam to top a latte. It dissolves into a shapeless cloud.

"That last bit is nearly impossible," he says, wiping his hands on his apron. He turns to the next customer in line and shrugs his shoulders helplessly, "Uh. This is what I do for fun."

It's rare to get the chance to try out a new job without ditching the safe one that pays the bills. Yet Jensen is one of many midlife professionals using their vacation time to do just that.

Jensen's stint at the Fuel Coffee business comes courtesy of his wife, who bought him a "dream job" from VocationVacations, a Portland-based company that, for a price, gives people a chance to test out a job they've always wanted. For Jensen it's a taste of entrepreneurship, the experience of running a small coffee shop.

The dream job could be making cheese at Pike Place Market for $349; working as a pet detective in Fresno, Calif. ($799); learning the alluring cowboy-boot business in Guthrie, Okla. ($2,999); or strutting around Los Angeles for two days with Gwen Stefani's choreographer for a modest $1,399.

Dream vacations do not include forays into jobs like plumber, accountant or, least dreamy of all, mortgage broker.

VocationVacations clients are paired with a "mentor" who can teach them as much as possible about a job in a day or two.

Danielle Cone, 29, owner of Fuel Coffee, is Jensen's mentor. She stands behind him with calm, encouraging reassurance.

"No, that was great. He's doing great," she tells a small crowd of spectators gathered around the espresso machine.

Since starting her business a year and a half ago, Cone has had to work every single day, usually starting around 5 a.m. With a new Fuel shop opening in the Montlake neighborhood in four months, her schedule will not be slowing down.

"It's a fine line between dream job and nightmare," says Jensen with a grin, as he listens to Cone describe the challenge of owning and operating the business. The two days at Fuel have given him more on-the-job experience, he says, than if he'd volunteered or job-shadowed someone in his hometown of Long Beach, Calif.

"The idea that I'm working in Seattle behind a counter at a coffee shop is pretty cool," he says, eyeing the custom-painted espresso machine with Volkswagen racing stripes. "There is something about being behind that machine."

In the past seven years as a senior graphic-design director, Jensen has seen his company grow from 16 to 100 people and has watched the atmosphere change.

For years, he has secretly (until now) dreamed about opening a coffee shop but had "written it off as too difficult." Through this experiential vacation, he says he found that it could actually happen.

"He really took to it," says his mentor, Cone. "I think he could do it. He's analytic, and he'd be good at running his own business."

About 20 percent of the VocationVacations clients have gone on to change careers as a result of their experience, says founder Brian Kurth. He conceived the idea for the two-year-old company as he commuted from a lackluster job as director of project management for a phone company.

"I never bragged about what I used to do for work," says Kurth. "I'd be sitting around with friends in Chicago having a conversation and heads would just hit the spaghetti plates when I talked about my job."

Typical vacationers are between 35 to 50 years old, he says, and many have technical backgrounds or work in financial services. They're bored and unfulfilled, fitting the profile of many working Americans. Last year's Gallup Poll found that just 32 percent of U.S. workers actually "love" their job.

"Everybody in the world is going to do better at something they like," says Richard Bolles, author of the seminal "What Color is Your Parachute?" Bolles published the first edition of his classic career book in the 1970s and has spent his working life listening to people ask him how to find a job that is best for them.

But is a weekend or even a week of vacation enough to make such an important change? Bolles thinks there is more to it than that.

"The vocation-vacation idea is nice and would work for someone who already knows what they love to do," he says. "But it is a dilettante exercise in some ways. Most people don't want to put the work into sitting down and having to think about what they would love to do."

Kurth agrees, to an extent. "One can easily become immobilized by the amount of effort it takes to make a change," he says. "Taking a vocation vacation removes some of that fear."

"It's really just the first step. It's like a mini-mini internship without taking a sabbatical."

Kurt Dammeier, owner of Beecher's Cheese, has had about 15 people use their vacations to learn about the cheese business.

"There's a growing cadre of professional-style cheese mongers out there," he says. Vacationers who work at his Pike Place shop have the option of arriving at 4 a.m. and staying until 4 p.m., or they can just show up sometime around lunch, have a cheese sandwich and leave.

"Some people really want to get in there and understand how it works," he says. "Most are just out for a lark. I don't know if anybody has gone on to start a cheese shop after spending a day of their vacation here."

But a working vacation helped Sue Burton, 38, of Boston make a change. A year ago, she took a vocational vacation away from her financial services job at J.P. Morgan. She spent three days learning about television production.

Just six months later she quit her job and started doing freelance commercial production, making about the same wage she had at her former job.

Jensen is not so sure he'll give up his graphics job, but now he has a better idea of what owning a cafe would be like.

"It didn't occur to me before that you'd have to get down and work in the trenches, especially if you're hiring and training people," said Jensen, "And the coffee is much more of a precise art than I realized."

With that, he picked up his free T-shirt, coffee journals and printouts of business information and sat back in his chair. With mock confidence, he drew in his breath and announced, "Yeah, I think I'm ready."