Preheat oven to 350 degrees F.
Make the crust: in a food processor, pulse the graham crackers until fine crumbs form. Add the sugar and melted butter, and process until well combined. Transfer mixture to a shallow 9-inch tart pan with a removable bottom. Press down bottom and sides using a measuring cup. Place prepared crust on a sheet pan to prevent any crumbs from falling in the oven. Bake for about 10 minutes, until the crust is set, slightly golden brown and fragrant. Let cool slightly.
Meanwhile, whisk sweet condensed sugar with egg yolks, sour cream, key lime juice, and lime zest until a smooth mixture forms.
Pour the filling into crust and smooth out the surface. Place pie on a sheet pan, if you prefer. Bake for 16-18 minutes until filling is set on the edges. The center should be slightly loose. Cool completely at room temperature, and then chill for about 6 hours or overnight in the refrigerator.
Beat the heavy cream on high speed using a stand mixer or electric mixer, using whisk attachment, until soft peak forms. Incorporate sugar, vanilla, and lime zest, and continue to beat until stiff peaks form.
Decorate the pie using your favorite decorative pipe. Garnish with lime wedges. Enjoy!