Why go out for a burger you can make at home? And let's face it about those big fat "gourmet" burgers: With few exceptions anyone can buy and broil half a pound of prime beef with impressive results. What one cannot duplicate at home is your classic Castle burger, a roughly two-square-inch, two-bite patty not quite as thin as a communion wafer and producing perhaps not quite the same degree of spiritual ecstasy among true believers. But let's just say that Castles are an illusory experience one couldn't ever duplicate at home, probably because no home has a grill with a zillion years worth of accumulated grease on it. White Castles are the classics, of course. These aren't available down here, however, except in inferior frozen form in supermarkets. But still performing (live and in person!) since 1939, just a block west of I-95 in Miami, is Arnold's Royal Castle, where the succulent square slider is still supreme, and still sliding smoothly off the grill into $3.40 six-packs. Each diner will need at least two packs, unless you don't mind driving back an hour later -- which is always possible; Royal Castle is open 24 hours daily.