Blend for about 30 seconds, or until well blended.
Pour into 2 tall glasses.
Top with whipped cream and lemon zest, and enjoy!
Whipped cream, Lemon zest
Notes
It's best to use fresh lemon juice but you can use bottled juice if that is all you have. Just keep in mind that bottled is more acidic and can taste a bit harsh.
For a thicker shake, just add more ice cream or a handful of ice.