Process first 5 ingredients in a blender until smooth. Pour into a 9-inch square pan; cover and freeze 3 hours or until firm.
Process frozen mixture, in batches, in a blender until smooth. Cover and freeze again 3 hours or until frozen. Garnish, if desired.
Excellent combos in place of the blueberries:
Peaches + cinnamon
Mango + cardamom
(roast the above fruit in the oven @400F for 30 minutes and then blend--leave the skin on the peaches, peel the mangos)