Pineapple-Rosé Punch

Whisk rum, pineapple juice, grapefruit juice, and sugar in a pitcher or large bowl until sugar is dissolved. Chill until cold, at least 1 hour and up to 4 hours. Stir in rosé. Taste and add more sugar, if desired.

If using pineapples, cut off fronds and set aside for serving. Cut a ¼"-thick slice off the bottoms and tops so they will sit upright and won’t wobble. Cut pineapples in half crosswise. Working with 1 half at a time, use a paring knife to cut away flesh ½" from skin. Using a large metal spoon, scoop out flesh, being careful not to pierce the skin. Save flesh for another use.

Ladle punch into ice-filled pineapple halves or rocks glasses and garnish each with a couple of pineapple leaves, if using, and a grapefruit wedge.