1. Place strawberries and orange juice concentrate in a large bowl. Use the potato masher to crush berries and blend the ingredients well.
2. Pour a tablespoon of the berry mixture into each compartment of an ice-cube tray.
3. Freeze about 90 minutes, until each cube is the consistency of firm, not liquidy, slush. (If the sorbet freezes for too long, add the cubes to a zip-close bag and gently crush with a rolling pin until they're slushy.) Using a spoon, transfer the cubes from the tray to a bowl and stir together before serving.