Bitterness rating: 4/10. Though we love the blushing pink color from Ruby Red grapefruit, you also can use a yellow-fleshed variety, which will likely be less sweet. We find that a London-style gin works best here; the floral flavors of more botanical styles (such as new-wave gins) are likely to overpower the taste of the grapefruit.
How to Make It
Place grapefruit peel strips and rosemary sprig in a 2-cup glass measuring cup or a sturdy glass; sprinkle with sugar. Muddle mixture with a muddler or wooden spoon until the peels release some liquid, 30 seconds to 1 minute.
Add grapefruit juice and gin; stir until sugar dissolves. Remove and discard the grapefruit peel strips and rosemary sprig. Stir in tonic water. Pour into 2 ice-filled collins glasses; garnish with additional rosemary sprigs, if desired.