Ice, to fill shaker
1½ c. fresh pink grapefruit juice
¼ c. fresh lime juice
6 oz. vodka
2 oz. orange liquor, such as Cointreau or triple sec
1 large lime, cut into slices
Fill a cocktail shaker with ice and add all other ingredients.
Cover and shake vigorously to blend.
Remove lid and strain into martini glasses.
Garnish with slices of lime and serve immediately.