In a mixing bowl, combine softened cream cheese, fresh key lime juice, and powdered sugar. Beat until smooth and creamy, about 2-3 minutes.

Whip heavy cream in a separate chilled bowl on high speed until stiff peaks form, about 3-5 minutes. Gently fold whipped cream into the cream cheese mixture.

Crush graham crackers into fine crumbs. Mix with melted unsalted butter until the mixture resembles wet sand.

In a clear serving dish, layer the crust mixture and then the creamy filling alternately until all ingredients are used.

Cover the trifle with plastic wrap and refrigerate for at least 2-3 hours.

Just before serving, add a sprinkle of lime zest on top, and optionally garnish with whipped cream or lime slices.