01 - Combine crushed cookies and melted butter in a bowl, mixing until evenly moistened. Press the mixture firmly into the bottom of a 9x13 inch dish. Refrigerate while preparing the blueberry layer.
02 - Add blueberries, granulated sugar, lemon juice, and water to a medium saucepan. Cook over medium heat until the berries begin to burst. Whisk cornstarch with a small splash of water to form a slurry, then stir it into the berry mixture. Simmer for about 2 minutes until thickened. Remove from heat and let cool completely.
03 - Beat cream cheese and powdered sugar together in a large bowl until smooth and lump-free. Incorporate lemon zest and lemon 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 in two additions, being careful 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 and remaining blueberry sauce, working carefully to maintain clean layers.
05 - Cover the dish tightly with plastic wrap and refrigerate for at least 4 hours, or overnight for the cleanest slices and best texture.
06 - Spread whipped cream over the top layer just before serving. Garnish with fresh blueberries and a sprinkle of lemon zest. Slice into 12 portions and serve chilled.