Here's a recipe for a classic Cosmopolitan cocktail:

Ingredients:

• 1 1/2 ounces (45 ml) vodka
• 1 ounce (30 ml) cranberry juice
• 1/2 ounce (15 ml) triple sec
• 1/2 ounce (15 ml) freshly squeezed lime juice
• Ice cubes
• Lime twist or orange peel, for garnish (optional)

Instructions:

1. Fill a cocktail shaker with ice cubes.
2. Add the vodka, cranberry juice, triple sec, and lime juice to the shaker.
3. Shake the mixture vigorously for about 15-20 seconds to chill the ingredients and mix them thoroughly.
4. Strain the cocktail into a chilled martini glass.
5. If desired, garnish the drink with a lime twist or a twist of orange peel. You can express the oils from the twist over the drink by gently squeezing it to release its fragrance.

Note: Some variations of the Cosmopolitan call for a splash of fresh orange juice or a sweetener like simple syrup, but the recipe above represents the classic version. Adjustments can be made to suit individual preferences.

Enjoy your homemade Cosmopolitan responsibly!