Place the graham crackers and sugar into a food processor and run at high speed until the crackers are in very fine crumbs. Turn the processor down to low speed, and slowly pour in the melted butter. Continue processing until all the crumbs are coated in the butter.
12 whole graham crackers, 2 tablespoons granulated sugar, 8 tablespoons (1 stick) butter
Firmly press the crumbs into the bottom of a 9x13 baking pan. Freeze for 20 minutes.
In a medium bowl, use a whisk to combine the lemon instant pudding and half and half milk until it's combined well and starts to thicken. Allow it to sit for 5 minutes so it can get even thicker.
1 box (3.4 oz) instant lemon pudding, 1½ cups half and half
In a separate larger bowl, beat the cream cheese and powdered sugar until smooth and no lumps remain in the mixture.
8 ounces cream cheese, 1/2 cup powdered sugar
Add in the thickened lemon pudding and blend on low speed to combine.
Add the Cool Whip and stir with a wooden spoon or silicone spatula until combined well.
8 ounces Cool Whip
Evenly spread the lemon cheesecake mixture over top the crust.
Pour the blueberry pie filling over top and spread it out. It may not go all the way to edge and that's ok. Just spread it out as best you can.
1 can (21 oz) blueberry pie filling
Layer the remaining tub of Cool Whip over top the blueberry filling and spread it out. Cover the pan with plastic wrap. Refrigerate for at least 8 hours or up to overnight is even better. You can garnish with crushed graham crackers, fresh blueberries and/or lemon slices if wanted.
8 ounces Cool Whip
When ready to serve, you can garnish each slice or the layered dessert with crushed graham crackers, fresh blueberries and/or lemon slices if wanted.