1/2 fresh pineapple, peeled, cut into 1½-inch pieces
6 ounces sweetened cream of coconut (preferably Coco López)
2 ounces unsweetened coconut milk
8 ounces white rum
2 tablespoons fresh lime juice
2 ounces dark rum (optional)
Maraschino cherries and lime wedges (for serving)
Place pineapple pieces in a resealable plastic bag, laying them flat. Freeze until solid, at least 3 hours.
Shake cream of coconut and coconut milk in their cans before measuring. Purée pineapple, cream of coconut, coconut milk, white rum, lime juice, and 3 cups ice (about 15 oz.) in a blender until smooth. Transfer blender cup to freezer and freeze until mixture is thickened (it should be the consistency of a milkshake), 25–35 minutes.
Blend again until mixture is the perfect slushy frozen drink consistency. Divide among glasses. Top off each with ½ oz. dark rum, if using, and garnish each with a cherry and lime wedge.
Do Ahead: Pineapple can be chopped 3 months ahead. Keep frozen.
From Bon Appetit