Thaw frozen berries in package.
Place thawed berries, juices, sugar and vanilla extract into blender and blend until liquified.
Strain berry-juice mixture through small sieve (to remove seeds) into a flat, freezer-safe container (I use a 9x9 Pyrex dish).
Cover with plastic wrap, making sure wrap touches entire surface and freeze for about an hour, or until firm. Serve with a sprig of fresh mint, if desired.
If frozen longer than an hour, you may need to allow the sorbet to stand at room temperature for it to soften enough to serve.
Also makes great popsicles or ice cubes for fruit drinks!

Serves 12