An epic burger, at a bookstore? Believe it. This test case of B&N’s new restaurant concept is wowing shoppers with modern, carefully crafted fare, including a gotta-try burger. The weighty, deeply flavorful patty is brisket-fortified chuck, and the salty, loosely packed meat is cooked just until the center goes from crimson to deep pink. Condiments include tender butter lettuce, an impressive swipe of Dijonnaise, crunchy raw red onions, a layer of vinegary pickles and a sharp Cheddar. Three cheers for the toasty brioche bun. It’s served with addictive fried potatoes.