Generic name, back-alley entrance — check, check. Menu board, speedy straight-to-the-point service — check, check. Pocket change, full belly — check, check. U-City Grill in the Loop has all the hallmarks of your perfect greasy spoon, except that the basic fill-'er-up is bibimbap with bulgogi beef: Korean comfort food. Grab a vinyl-seated stool at the counter, and with little more than a nod from you, Yong Sup Sim or his wife So La Sim will soon be sizzling your marinated beef, scooping your sticky rice and chopping your vegetables for a brimming bowl of awesomeness, topped with a fried egg and Korean hot sauce. The vegetables — carrots, cucumbers, sprouts, shredded lettuce — are nothing exotic, and there's no ice in your water glass, but for a colorful swirl of belly-lining flavor for less than $7, U-City Grill amounts to nothing short of an American classic.