No-Bake Key Lime Pie

In a medium bowl, combine graham cracker crumbs and 6 tablespoons of melted butter. If needed, add 1 more tablespoon of melted butter at a time until the mixture resembles wet sand.
Press the crumb mixture firmly into the bottom and up the sides of a 9-inch pie dish. Chill in the refrigerator while preparing the filling.
In a large bowl, beat the softened cream cheese until smooth. Gradually add sweetened condensed milk and key lime juice, mixing until well combined. Stir in key lime zest.
In a large or medium bowl, whip cold heavy cream to stiff peaks. Combine with cream cheese mixture and gently fold to combine.
Transfer the filling into the prepared crust and smooth the top with a spatula.
Refrigerate the pie for at least 4 hours, or until the filling is firm.
Before serving, garnish with whipped cream and key lime slices.