3/4 cup plus 1 tablespoon grapefruit juice, divided
1 tablespoon coarse salt
1 1/2 ounces vodka
Dip rim of glass in 1 tablespoon grapefruit juice; dip in a shallow dish of coarse salt to coat rim of glass. Fill serving glass with ice cubes; pour vodka and remaining grapefruit juice over ice. Stir and serve immediately.