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 ts 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.