Preheat oven to 450 degrees F. Prepare a 9-inch pie shell, prick crust every inch around sides and bottom, and bake for 12 minutes, or until barely brown. Set aside to cool.
Beat egg yolks until thick and lemon colored. Add half the sugar, pumpkin, milk, and spices. Cook until thick, about 180 degrees, in top of double boiler over gently boiling water. Dissolve gelatin in cold water and add to squash mixture. Cool. Beat egg whites and remaining sugar until stiff. Then fold into cooled gelatin-squash mixture. Pour into baked shell and chill until firm. Serve topped with whipped cream.