Since the pandemic, Joshua Pollack’s New York-inspired restaurant group “has really changed how we think about growth,” he said.
After he closed Rosenberg’s Bagels in Boulder in October 2022, a little over a year after opening, Pollack was hesitant to take another risk.
“At some point, we will open more Rosenberg’s, pizza places and maybe even another Lou’s,” Pollack said. “But for now, we really want to bring forth food we enjoy and share it without the rigmarole of opening a restaurant. We wanted to use Rosenberg’s at night and try out some pop-ups of things we’ve been thinking about for a long time,”
Starting this month until Labor Day, Rosenberg’s Bagels at 725 E. 26th Ave. in Five Points is hosting a late-night slider pop-up dubbed RosenBurger’s from 5 p.m. to 2 a.m.
“It made the most sense to activate our space in a neighborhood we already have such a relationship with,” Pollack said.
All of Pollack’s Bridge & Tunnel restaurants, including Famous Original J’s Pizza and Lou’s Italian Specialties, pay homage to his upbringing in New Jersey and New York. And RosenBurger’s is no exception. The pop-up is modeled after White Manna, an old-school burger institution that started at the World’s Fair in 1939 and later moved to Hackensack, N.J., in 1946.
“It’s this gem of nostalgia and Americana from the early 1900s,” Pollack said. “I grew up going there, and these were like the original fast-food burgers. It’s a small little hut with a flattop in the center, and you always leave smelling of onions and burgers.”
Like White Manna, RosenBurger’s will serve simple sliders with cheese, pickles, ketchup, mustard, an in-house special sauce and white onions that are smashed into the beef patty. The beef, which will be sourced from local producers, is ground fresh daily. And Pollack worked hard with his provider to secure specific Martin’s potato slider buns.
“We work hard to keep all the details as exact as possible, just like with our New York water rat Rosenberg’s,” he said, referring to the special water filtration system that Rosenberg’s use to mimic the water levels in New York for its authentic bagels.
One slider goes for $3.80 (or a double for $6.70), and a “Party Sack” ($50) comes with 10 sliders and four orders of fries. The pop-up, which delivers, also offers simple shakes, malts and pastries.
“I can usually eat between three and four, but I’ve been working the last two weekends there as we’ve been testing it out, so I’ll start eating at 5 p.m., and by one in the morning, I’ve had like six of these things,” Pollack said.
Pollack has seen a new energy in Five Points since the summer kicked off, especially with concerts at Cervantes every weekend and late-night traffic from The Marigold and 715 Club nearby.
“When I moved here, there were no good bagels, pizzas or hoagies, so that’s where all my ideas came from, but there was also no late-night food,” Pollack said. “Famous Original J’s Pizza next door is open until 2 a.m., and we’ve seen such success there. With the amount of vacancies on the Welton Street Corridor, we’re excited to champion the nightlife there. The more active you can make it, the more traffic and less crime there will be.”
If RosenBurger’s “really has legs,” Pollack said he will consider keeping it in the Ronseberg’s space or find it its own brick-and-mortar for year-round service. But he does have plans to test out other pop-ups, like a taco concept modeled after Los Tacos No. 1 in New York City, and high-end deli food.