San Franciscans may have branded the burrito as the city's cheap-eats favorite, but even the most dedicated taqueria habitué knows you can only scarf carne asada six days a week. On the seventh, consider Philadelphia's ode to lunchtime bliss: the cheesesteak sandwich. It's a basic formula: thin-sliced beef grilled on a flattop, smothered in cheese, and slapped into a bun with grilled onions and pickled peppers. The aptly named Cheese Steak Shop, Divisadero's most popular eatery, is dedicated to the original Philly formula. Don't be fooled by Niman Ranch this or whole-wheat bun that at other sandwich shops. The real thing is a belly beast that isn't improved by fancy ingredients or lengthy preparations. The Cheese Steak Shop has its sandwich down to an art: a greasy, cheese-soaked monster that comes in 6-inch, 10-inch, or 15-inch increments, served in buns flown in from the city of Brotherly Love. There are half a dozen or so varieties (pizza steak, mushroom steak, barbecue steak, etc.) as well as chicken versions of everything, but the uninitiated need only order the plain cheesesteak to understand the shop's motto ("Caution: May be habit forming"). An added bonus: Philadelphia's much-loved Hostess alternative, Tastykakes, are also on the menu.