Place the yogurt, berries, and the milk in a blender. Blend on high for 30 seconds. Use the smaller amount of milk if your berries are juicy, the greater amount of milk if they are not.
Add the ice cubes and blend on high for another minute. Taste the smoothie and adjust the sweetness with honey, sugar or Splenda. Add 1-2 drops extra strong flavoring. Adjust the thickness with more fruit or milk if needed, and blend for an additional 30 seconds. Pour into tall frosty glasses and enjoy.