01 -
Use a 9x13-inch baking dish. Lightly coat it with cooking spray if desired.
02 -
Beat the lemon pudding mix with cold milk for about 2 minutes, until thickened. Fold in the thawed whipped topping and lemon zest until smooth.
03 -
Place one layer of whole graham crackers across the bottom of the dish. Break crackers as needed to cover the corners.
04 -
Spread half of the lemon filling over the crackers. Add a second layer of graham crackers, then spread on the remaining filling.
05 -
Cover the filling with a final even layer of graham crackers, pressing gently so the top is level.
06 -
Microwave the lemon frosting uncovered for 25-35 seconds, just until pourable. Stir, pour over the top crackers, and spread evenly.
07 -
Cover and refrigerate for at least 12 hours or overnight. Slice cold and garnish with lemon slices or zest if desired.