In a mixing bowl, combine crushed graham crackers with melted butter and sugar. Press this mixture evenly into the bottom of a greased 9x9-inch baking pan. Bake at 350°F for 10 minutes until lightly golden.

In another bowl, blend cream cheese, powdered sugar, and limoncello until smooth and creamy.

Once the crust has cooled slightly, pour the limoncello filling over it, smoothing it into an even layer.

Cover the pan with plastic wrap and refrigerate for at least 4 hours or until firm.

Once set, slice into squares for serving. Garnish with a sprinkle of lemon zest or a dusting of powdered sugar.