01 - Combine crushed vanilla wafers or graham crackers with melted butter in a mixing bowl. Press the mixture firmly and evenly into the base of a 9x13-inch baking dish. Set in the freezer while assembling the subsequent layers.
02 - Beat softened cream cheese until completely smooth. Add powdered sugar, lemon juice, and lemon zest; mix until fully incorporated. In a separate bowl, whip heavy cream until stiff peaks form, then gently fold into the lemon-cream cheese mixture. Spread evenly over the chilled cookie crust.
03 - In a saucepan over medium heat, combine blueberries, granulated sugar, and lemon juice. Stir and cook until berries begin releasing juice, about 4 to 5 minutes. Blend in the cornstarch-water mixture, stirring until the sauce thickens, 2 to 3 minutes. Remove from heat and let cool completely.
04 - Once cooled, gently spread the blueberry mixture over the lemon layer using a spatula for even coverage.
05 - In a clean bowl, beat heavy cream, powdered sugar, and vanilla extract to stiff peaks. Smoothly apply over the blueberry layer. Top with lemon zest and fresh blueberries, if desired.
06 - Refrigerate uncovered for at least 4 hours or overnight to allow layers to set. Slice with a sharp knife and serve chilled.