We halve them, scoop out the flesh into a large bowl and add a spoon of honey. The bowl is then put in the fridge and the honey reacts, making it appear that they have been stewed. A potion is then taken each morning for breakfast.
In the picture, the one on the left is normal but the other on the right is the equivalent of a double-yoker egg. I have scooped out thousands of them but this is the first I recall ever seeing. For those who don't know the fruit, they may both seem normal, but it is an exception.
So if you toss about at night unable to sleep because you have pondered whether a feijoa fruit can be a double version, you can now rest easy. It's happens.