In a medium bowl, combine graham cracker crumbs, granulated sugar, and melted butter. Mix until the crumbs are evenly coated. Press the mixture into the bottom of 6 small jars or cups to form the crust layer. Set aside.

In a large mixing bowl, beat the softened cream cheese with an electric mixer until smooth and creamy. Gradually add the powdered sugar, mixing until well combined.

Add the sour cream, key lime juice, lime zest, and vanilla extract to the cream cheese mixture. Beat on medium speed until everything is well incorporated and smooth.

Spoon the cheesecake filling evenly into the jars over the crust layer. Smooth the tops with a spatula.

Cover the jars with lids or plastic wrap and refrigerate for at least 4 hours, or overnight for best results.

Before serving, top each jar with whipped cream and garnish with a slice of lime.