Place all of the ingredients in a large blender, or make two half batches in a smaller blender.
Cover and blend until well combined. You may need to pause blending and stir to help things out.
Pour the mixture into a large freezer-friendly container (a glass baking dish or bowl works great) and freeze for at least 6 hours.
Take the container out of the freezer and break up the wine mixture with a fork. Spoon the slushie into wine glasses, garnish with berries and a sprig of mint if desired, and enjoy!
Notes
You can start this recipe without any added sugar. Once everything is blended give the mixture a taste and blend in the sugar if desired.
I used a combination of red raspberries, blackberries, and blueberries for the fruit, but you can use whichever frozen berries you prefer.