Separate a ½ cup of pineapple juice from the can, then drain the rest.

Place pineapple chunks in a freezer-safe container or plastic bag and freeze for a few hours or overnight.

Place pineapple juice, buttermilk, vanilla, and your sugar source in a blender with the frozen pineapple. Cover with blender lid, and mix on medium-high until smooth. Add water as needed if too thick.

Serve and enjoy!