In a cocktail shaker with ice, combine the vodka, blue curacao and lemonade.
Shake for 10-15 seconds until well chilled.
Strain and pour into a glass with fresh ice. Garnish with a lemon slice and a maraschino cherry.
Notes
If you don't have lemonade on hand, you can easily substitute fresh lemon juice and simple syrup to mix this drink up.
The truth is this recipe has many famous versions—some using lemon-lime soda and some that are blended. This recipe is flexible and open to substitutions.
The best kind of ice for a blue lagoon is crushed ice.