Mix the wine, liqueur, and simple syrup together and pour into ice trays. Freeze for 2 hours.
After freezing, add wine cubes to blender with frozen fruit.
Pulse for a few seconds to break everything apart then blend on high until smooth, about 45 seconds.
Add ice if slushie not quite frozen enough and blend again until smooth.
Pour into chilled stemless wine glasses and garnish with extra frozen fruit, if desired. Serve immediately.
Notes
*Simple syrup is made by simmering equal parts sugar and water until sugar is dissolved. Let cool and store in airtight container in the fridge for up to a month.*Addition of simple syrup is optional depending on how sweet your base wine is and how sweet you want your sangria to be.