Preheat oven to 375F.
Put together Graham cracker crumbs, sugar, and butter with a spatula in a small bowl.
Spray the pie pan with cooking spray.
Fill the bottom of the pie pan by gently pressing the crumb mixture evenly.
Bake the crumb mixture for 7 minutes.
Remove from oven and let it sit for at least 30 minutes.
Preheat oven to 350F.
With a whisk, mix together the sweetened condensed milk, sour cream, lime juice, and lime zest in a medium bowl.
Pour the mixture over the prepared Graham cracker crust and bake for another 10 minutes.
Cool the pie for a few minutes (preferably at room temperature before chilling).
Refrigerate the pie for at least 3 hours.
Whisk heavy cream and sugar together in a stand/handheld mixer until stiff peaks form.
Add in vanilla extract and fold the mixture altogether.
Transfer into a piping bag and then swirl the whipped cream around the top of the cooled pie.
Note: You can frost the pie according to your own tastes and preference.
Garnish the top with additional sprinkled lime zest.