Prepare the Crust: In a medium bowl, combine crushed graham crackers with melted butter, mixing until it resembles wet sand. Press the mixture firmly into the bottom of a large trifle dish to form an even layer.

Make the Cheesecake Filling: Beat softened cream cheese with an electric mixer until smooth and creamy. Gradually add sweetened condensed milk, lime juice, lime zest, and vanilla extract, mixing until fluffy.

Whip the Cream: Chill a mixing bowl and beaters for 15 minutes. Whip heavy cream on medium-high speed until soft peaks form. Gradually add powdered sugar and whip until stiff peaks form.

Combine Mixtures: Gently fold the whipped cream into the cream cheese mixture using a spatula to maintain fluffiness.

Assemble the Trifle Layers: Layer half of the cheesecake filling over the crust, followed by a layer of graham cracker crumbs, and repeat with the remaining filling. Smooth the top.

Chill the Trifle: Cover with plastic wrap and refrigerate for at least 2 hours.

Garnish and Serve: Garnish the top with lime slices and zest. Serve chilled, optionally adding a dollop of whipped cream.