To a cocktail shaker add vodka, lime juice, triple sec, and cranberry juice. Add ice and cover the shaker. Shake until well chilled.
Strain into a chilled cocktail glass and garnish with a lime slice.
Notes
Vodka: Some versions of the cosmo are made with citrus-flavored vodka. Unflavored works, too.
Triple sec: Or any orange-flavored liqueur such as Cointreau or Grand Marnier.
Yield: This recipe makes 1 Cosmopolitan cocktail.
Glassware: The Cosmo is traditionally made in a cocktail glass (martini glass). But, it is not actually a type of martini.
Big batch: To make a batch of 8 cocktails, combine 12 oz. (1 1/2 c.) Prosecco, 2 oz. (1/4 c.) lime juice, 2 oz. (1/4 c.) triple sec, and 2 oz. (1/4 c.) cranberry juice in a pitcher. Have ice, glassware, and garnishes on hand so guests can help themselves.
Sea Breeze: Made in a highball glass. Substitute 6 oz. (3/4 c.) grapefruit juice for the triple sec and increase the cranberry juice to 2 oz. (1/4 c.).
Cape Codder: AKA a vodka cranberry. Add 1 1/2 oz. (3 Tbsp.) vodka to a highball glass filled with ice, then top with cranberry juice. Garnish with a lime wedge.
Kamikaze cocktail: In a cocktail shaker filled with ice, ad 1 1/2 oz. (3 Tbsp.) vodka, 1 oz. (2 Tbsp.) orange liqueur, and 1 oz. (2 Tbsp.) lime juice. Shake until chilled, then strain into a martini glass. Garnish with a lime wedge. For a kamikaze shot, combine 1 oz. (2 Tbsp.) vodka, 2 tsp. orange liqueur, and 2 tsp. lime juice in a shot glass.
Non-alcoholic: Replace the triple sec with orange juice and the vodka with pink lemonade.