01 - Combine crushed cookies and melted butter in a bowl, mixing until evenly coated. Press the mixture firmly into the bottom of a 9x13 inch dish. Refrigerate while preparing the remaining layers.
02 - Add blueberries, sugar, lemon juice, and water to a saucepan over medium heat. Cook until the berries begin to burst. Dissolve cornstarch in a small splash of water to form a slurry, then stir it into the berry mixture. Simmer until thickened, about 2 minutes. Remove from heat and let cool completely.
03 - Beat cream cheese and powdered sugar together until smooth and free of lumps. Incorporate lemon zest and juice, mixing until well blended. In a separate bowl, whip cold heavy cream to stiff peaks. Gently fold the whipped cream into the lemon mixture until just combined, taking care not to deflate the volume.
04 - Spread half of the lemon cream evenly over the chilled cookie crust. Spoon half of the cooled blueberry sauce over the cream layer, spreading gently. Repeat with the remaining lemon cream followed by the remaining blueberry sauce.
05 - Cover the dish tightly and refrigerate for at least 4 hours, or overnight for the cleanest slicing results.
06 - Spread whipped cream over the top layer just before serving. Garnish with fresh blueberries and a dusting of lemon zest. Slice into portions and serve chilled.