Lime Sour Cream Pie

For the filling:
1 1/2 tablespoons freshly grated lime zest
1/2 cup fresh lime juice
1 cup half-and-half
3/4 cup sugar
2 tablespoons unsalted butter, softened
5 tablespoons cornstarch
3/4 cup sour cream

Sweetened whipped cream for garnish
Lime slices for garnish

Make the crust: In a bowl stir together the graham cracker crumbs
and the butter and press the mixture onto the bottom and up the side
of an 8-inch pie plate (1-quart capacity). Bake the crust in the middle
of a preheated 350-degree F. oven for 8 to 10 minutes, or until it is
just crisp, and let it cool.
Make the filling: In a metal bowl set over a saucepan of barely
simmering water whisk together the zest, lime juice, half-and-half,
sugar, butter, and cornstarch, and cook the mixture, whisking, for
5 to 7 minutes, or until it is thickened and opaque. Let the mixture
cool completely. Fold in the sour cream, pour the filling into the crust
and chill the pie, covered, for 1 hour, or until it is cold. Garnish the
pie with the whipped cream and the lime slices.