For the crust:
   1 1/2   c            Fine graham cracker crumbs
   2       tb           Sugar
     1/4   c            Unsalted butter, melted and
                        Cooled
                        For the filling:
   1 1/4   lb           Cream cheese, softened
     3/4   c            Sugar
   1       c            Sour cream
   3       tb           All-purpose flour
   3       lg           Eggs
     3/4   c            Key lime juice
   1       t            Vanilla
   1       dr           Green food coloring, if
                        Desired
                        Whipped cream for garnish
                        Lime slices, quartered for
                        Garnish
                        Mint sprigs for garnish
  Make the crust:  In a bowl stir together the crumbs and the sugar and
  stir the butter in well.  Pat the mixture evenly onto the bottom and
  1/2 inch up the side of a buttered 10-inch springform pan and bake
  the crust in the middle of a preheated 375F oven for 8 minutes.
  Transfer the pan to a rack and let the crust cool.
  In a bowl with an electric mixer, beat together the cream cheese and
  the sugar until the mixture is smooth; beat in the sour cream, the
  flour, the eggs, 1 at a time, beating well after each addition, the
  lime juice, the vanilla, and the food coloring, and beat the mixture
  until it is smooth. Pour the filling over the crust.  Bake the
  cheesecake in the middle of a preheated 375F oven for 15 minutes,
  reduce the temperature to 250F, and bake the cheesecake for 50 to 55
  minutes more, or until the center is barely set.  (The cheesecake
  will continue to set as it cools.) Let the cheesecake cool on a rack
  and chill it, covered, overnight.
  Remove the cheesecake from the pan and transfer it to a cake stand.
  With a pastry bag fitted with a decorative tip, pipe the whipped
  cream into rosettes on the cheesecake.  Garnish the cheesecake with
  the lime slices and the mint sprigs.