In a mixing bowl, combine graham cracker crumbs with melted unsalted butter. Press mixture into the bottom of a trifle dish or serving bowl.

Chill a mixing bowl and beaters in the freezer. Beat heavy whipping cream until stiff peaks form.

In a large mixing bowl, beat softened cream cheese until smooth. Gradually add powdered sugar, key lime juice, key lime zest, and vanilla extract.

Gently fold the whipped cream into the cream cheese mixture.

Layer half of the creamy lime filling over the crust in the trifle dish. Repeat with remaining filling, smooth it out, and finish with reserved crumbs and lime zest.

Cover with plastic wrap and refrigerate for at least 2 hours.