Preheat oven to 350 degrees F. Prepare pan: 9-inch cheesecake pan, ungreased, or springform pan with 3-inch sides, greased.
Crust
In a medium bowl, combine graham cracker crumbs, almonds, and butter.
Press into bottom of cheesecake pan and freeze.
Filling
In a mixer bowl fitted with paddle attachment, beat cream cheese, butter and sugar on medium-high speed until very smooth, for 3 minutes.
Add eggs, one at a time, beating after each addition.
Stir in sour cream, orange juice concentrate, orange zest and vanilla.
Fold in orange segments by hand.
Pour over frozen crust, smoothing out to sides of pan.
Bake in preheated oven until top is light brown and center has a slight jiggle to it, 45 to 55 minutes. Let cool on the counter for 10 minutes (do not turn the oven off). The cake will sink slightly.
Topping
In a small bowl, combine sour cream, sugar and orange juice.
Pour into center of cooled cake and spread out to edges.
Bake for 5 minutes more. Let cool in pan on a wire rack for 2 hours.
Cover with plastic wrap and refrigerate for at least 6 hours before decorating or serving.
Decoration
In a well-chilled bowl, whip cream on medium-high speed until soft peaks form. With the mixer still running, sprinkle sugar into cream and continue whipping until firm peaks form.
Ice top of cheesecake or pipe a border around cake, if desired.