See what it's like to eat at the wildly popular fast-food chain that was endorsed by the world's greatest chef

It may be called Beefsteak, but top chef Joan Roca's favorite fast food restaurant is all about the vegetables.

The trendy chain, which boasts just a handful of locations across the American Northeast, focuses most of its energy on produce. In a concept created by internationally-renowned Spanish chef José Andrés, veggies take center stage in a variety of innovative dishes that are prepared on the spot. 

"It's gastronomic yet economic: tasty food for a society where people have no time," Roca told Bloomberg. Roca's own restaurant - El Celler de Can Roca, in Girona, Spain - has several times been named the best restaurant in the world by the Diner's Club 50 Best Restaurants Academy, which is made up of close to 1,000 restaurant industry leaders from around the world. Though El Celler de Can Roca fell to number-two on the list this year, Roca himself was given the Chefs' Choice Award for his influence on the dining world. 

If Roca says Beefsteak is good, it has to be. Here's a closer look at what makes the fast-food restaurant stand out for him, and for the hordes of others who have lined up to be served.