Combine all 3 ingredients into a freezable container.
Place in the freezer overnight/for 8 hours, remove and mess it around with a fork.
Put back in the fridge for another 8 hours.
Remove when the mixture is full of chunky ice crystals and serve in a bowl with a teaspoon and a twist of grapefruit (or paper snow cone style cup if you want the real deal).
Serves 4 – 6 and is guaranteed to knock the flip flops off your guests.