Prepare the graham cracker crust by crushing the graham crackers in a food processor until fine crumbs form. Combine the crumbs with granulated sugar and melted butter, mixing until well blended. Press this mixture into the bottom of a 9x13 inch dish and freeze for 20 minutes.

In a medium mixing bowl, whisk together the instant lemon pudding and half and half until the mixture thickens, about 5 minutes. Make sure it's smooth and creamy before proceeding.

In a separate bowl, beat the softened cream cheese with powdered sugar until smooth. Fold the thickened lemon pudding into the cream cheese mixture until fully incorporated, ensuring there are no lumps.

Gently fold half of the Cool Whip into the lemon cream cheese mixture. Spread this mixture evenly over the chilled graham cracker crust.

Pour the blueberry pie filling over the lemon layer, spreading it gently. Leave a slight border around the edges for a rustic appearance.

Spread the remaining Cool Whip over the blueberry filling. Cover with plastic wrap and refrigerate for at least 8 hours, preferably overnight.

When ready to serve, slice into squares and garnish with additional toppings if desired. Serve chilled.