2 1/2 cups freshly squeezed orange juice, plus orange sections for garnish (optional)
3/4 cup plain yogurt
1 banana, peeled and halved
3 tablespoons honey
1/4 teaspoon ground cinnamon, plus more for garnish
Fill one ice-cube tray with pineapple juice and another tray with orange juice. Place in the freezer until frozen, several hours or overnight. Place yogurt, banana, honey, and cinnamon in the jar of a blender, and process until smooth. Transfer to a bowl, and set aside. Rinse blender, and fill with pineapple ice cubes and remaining pineapple juice. Process until smooth.
Divide among four glasses, top with reserved yogurt mixture, and place in the freezer. Meanwhile, process the orange-juice cubes with the remaining orange juice. Remove filled glasses from freezer, and top with orange-juice slush. Garnish each glass with additional cinnamon and an orange section, if desired. Serve immediately.