Step 1

Place pineapple pieces in a resealable plastic bag, laying them flat. Freeze until solid, at least 3 hours.

Step 2

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.

Step 3

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.

Step 4

Do Ahead: Pineapple can be chopped 3 months ahead. Keep frozen.