2 packages lemon pudding mix
1 (8 oz) container Cool Whip
3 cups whole milk
1 (16 oz) package graham crackers
½ cup (1 stick) butter, softened
2 cups powdered sugar
2 tablespoons milk
2 tablespoons lemon juice
Line a 9×13 inch pan with parchment paper or aluminium foil, then cover completely with one layer of graham crackers, breaking the grahams into smaller pieces to fill gaps.
In a large bowl, combine pudding packets, Cool Whip, and milk, and pour half of mixture evenly over grahams.
Add another layer of graham crackers, top with remaining pudding mixture, and one final layer of graham crackers.
In a separate bowl, combine all frosting ingredients. Start with one cup of powdered sugar and add more until frosting is at desired consistency.
Spread frosting evenly over cake, cover, and freeze for at least 4 hours or overnight.
Remove from freezer. Slice, serve, and enjoy!