Earlier this month, the restaurant Lunchbox Laboratory opened in the old Ballard Brothers Burgers space at 7302 15th Ave. So this weekend, we decided to give it a try. To our surprise, it was jam packed already. The tiny, retro-contemporary spot specializes in comfort food like its Simpson tuna casserole, sweet chile fried fish, My Reuben sandwich and various other experiments (even “TV dinners.”) But its speciality is burgers — every conceivable kind of burger with sides like mac & cheese and beenie weenies. Tasty stuff, but be warned: bring your appetite, as each serving is massive.

The only drawback is the restaurant’s very small size. Get ready to know your neighbor up close and personal, unless it’s sunny and warm — there’s plenty of seating outside. The decor is retro cool, including vintage lunchboxes.

The new restaurant is the brainchild of chef Scott Simpson, who created the Blue Onion Bistro and Fork. But as this Seattle PI profile explains, he ate his way to 469 pounds and had to take some time off. Now he’s down to 200 pounds and back in business with Lunchbox Laboratory. And it looks like he has another hit on this hands. (Closed Tuesdays).