Miracle crust from the master  City Bakery owner Maury Rubin
really knows pies and tarts -- and he's willing to share.  By
Betty Hallock  Los Angeles Times Staff Writer     Maybe his tart
crust is magic because it was the beginning of something --
something big -- born from time spent in an Upper West Side
apartment testing recipes and staring at the wall as he
contemplated starting his first bakery. In 1990, Rubin opened
the original City Bakery near Manhattan's Union Square, and his
tarts would become famous (he's written a book about them, aptly
titled "Book of Tarts"). In February, after months of public
anticipation, he opened the second City Bakery in the Brentwood
Country Mart.  Conventional wisdom would have you believe that
making a great crust is difficult. A pie crust should be flaky,
a tart crust crisp, and you jump through hoops trying to achieve
that, because what is a pie or tart without a good crust? A
disappointment. So you worry about whether your butter is cold
enough. You stare into the bo