The family-owned chain has been successful enough to spawn a famous commercial jingle, earn several loving write-ups in the New York Times and have its burgers served to A-list celebs at swanky post-Oscar parties. The great taste hasn't changed, but the mystique that inspired our carnivorous cross-valley quests sure has. The earlier, spartan drive-throughs, which once kept us at arm's length, a sheet of glass sealing off the inner sanctum where clean-cut workers frenetically packed the grill with meat patties, has given way to brightly lighted indoor seating no different from the national fast-food chains. The fabled secret menu, for...