Preheat the Oven (If Baking the Crust): Preheat the oven to 350°F (175°C). This step is optional and intended for those who prefer a firmer, lightly toasted crust. Alternatively, the crust may be refrigerated to set without baking.
Prepare the Graham Cracker Crust: In a mixing bowl, combine the graham cracker crumbs, melted unsalted butter, and granulated sugar. Stir until the mixture resembles wet sand and is evenly moistened.
Form the Crust Base: Transfer the crumb mixture into a 9-inch springform pan. Press it firmly and evenly into the bottom of the pan using the back of a spoon or flat-bottomed glass. If baking, place the crust in the preheated oven for 8 to 10 minutes, or until lightly golden. Remove and allow it to cool completely before adding the filling.
Prepare the Cream Cheese Mixture: In a large mixing bowl, beat the softened cream cheese with the granulated sugar using a hand mixer or stand mixer on medium speed. Continue beating until the mixture becomes smooth, creamy, and free of lumps.
Incorporate Flavor Elements: Add the vanilla extract, lime zest, and freshly squeezed lime juice to the cream cheese mixture. Beat until the ingredients are thoroughly combined, and the texture is light and silky.
Whip the Heavy Cream: In a separate mixing bowl, whip the heavy cream until stiff peaks form. Ensure the cream is well chilled prior to whipping for optimal volume and stability.
Combine the Mixtures: Gently fold the whipped cream into the cream cheese and lime mixture using a spatula. Take care to fold slowly and evenly to maintain the airy texture. Avoid overmixing to prevent deflation.
Assemble the Cheesecake: Pour the finished mousse filling over the cooled crust in the springform pan. Smooth the top surface with a spatula for a polished appearance.
Chill the Cheesecake: Cover the cheesecake and refrigerate for a minimum of 4 hours, or overnight for best results. The cheesecake should be set and firm before serving.
Garnish and Serve: Prior to serving, garnish the cheesecake with a generous dollop of whipped cream and decorate with lime slices and additional zest, if desired. Serve chilled.