Step 1: go to the store and buy green seedless grapes.
Step 2: wash them when you get home and then put them in the freezer for a couple hours.
Step 3: take them out of the freezer and enjoy!
See?! Easy peasy. The grapes never get frozen solid like ice cubes. Instead they get kinda slushie. SOOOO yummy! I've tried red/purple grapes but they just don't taste as great to me. But you may like it :) My dudes like to cut them in half and suck the slush out lol.
Hope you give it a try!