Fill a copper mug or a highball glass with ice cubes. The copper mug is traditional and helps keep the cocktail colder for longer, but a highball glass works just as well.

Pour Irish whiskey into the glass. The smooth and distinctive flavor of Irish whiskey sets the foundation for the cocktail.

Squeeze lime juice into the glass. The lime juice adds a zesty and tangy element to balance the sweetness of the ginger beer.

Top it off with ginger beer. The ginger beer provides a spicy and refreshing flavor that complements the Irish whiskey.

Stir gently with a cocktail spoon to combine the ingredients and distribute the flavors.

Garnish the cocktail with a lime wedge and a sprig of mint for visual appeal and an aromatic touch.