1/2 watermelon, cubed
3 bananas, sliced
3 (8 ounce) containers vanilla yogurt
2 tablespoons white sugar
1 tray ice cubes (optional)
Place watermelon, bananas, and yogurt in a blender; pulse for 20 seconds and continuously blend until smooth, about 30 seconds. Add sugar and blend on low for 5 seconds. Add ice and blend for 20 seconds. Place mixture in freezer until semi-frozen, about 1 hour.