In a large bowl, combine cool whip, yogurt, lemon zest, and lemon juice until well mixed.
Spoon mixture into graham cracker crust.
Place in freezer.
Before serving, remove from freezer and let thaw until it's "barely" frozen.
Garnish with whipped cream and lemon zest. Slice and serve.
**If only serving a few slices, remove from freezer, slice and plate as many serving as you need. Let thaw, then garnish and serve.