For the Graham Cracker Crust:

1. Preheat the Oven: Preheat your oven to 350°F (175°C) and line an 8×8-inch baking dish with parchment paper or lightly grease it.

2. Make the Crust: In a medium bowl, mix the graham cracker crumbs, sugar, and melted butter. Stir until the mixture is well combined and the crumbs are coated with butter.

3. Press into the Pan: Press the graham cracker mixture firmly into the bottom of the prepared baking dish to form an even crust.

4. Bake the Crust: Bake the crust for about 8-10 minutes or until golden brown. Remove from the oven and set aside to cool while you prepare the filling.

For the Key Lime Filling:

1. Prepare the Filling: In a large bowl, beat the softened cream cheese until smooth and creamy. Add the sweetened condensed milk and beat until fully incorporated.

2. Add Lime Juice and Zest: Stir in the key lime juice and lime zest. Continue mixing until everything is well combined and smooth.

3. Fill the Crust: Pour the lime filling over the cooled graham cracker crust and spread it evenly.

4. Bake the Bars: Bake the bars at 350°F (175°C) for 12-15 minutes, or until the filling is set but still slightly jiggly in the center. Let the bars cool to room temperature, then refrigerate for at least 2 hours or until fully chilled and firm.

For Serving:

1. Serve: Once the bars are chilled and set, cut them into squares. Top with a dollop of whipped cream, a slice of lime, and additional lime zest for garnish.