Slice the feijoas in half lengthways and scoop out the flesh. You will need two cups of tightly packed feijoa flesh.
Blitz the feijoa flesh in the chopping bowl of an immersion/stick blender until smooth. Strain through a fine fine sieve and discard the seeds.
Slice the flow off two feijoas and chop into pieces. Blitz the feijoas, with skin until relatively smooth. Strain and add to rest of the feijoas. This step is optional but will significantly add to the feijoa flavor of the ice cream.
Put the strained feijoa flesh into a small pot. Heat on low, stirring often, for about twenty minutes, or until has reduced by at least 25% (so you have one and a half cups remaining).
Add the sugar, cream and glycose syrup to the pot. Continue to heat on low and stir well until combined and all the sugar and syrup has dissolved.
Allow to cool and transfer to a heatproof container. Juice the lime and add the lime juice. Mix well.
Chill in fridge for at least four hours, preferably overnight.
Put your storage container in the freezer to chill. If you are using a self refrigerating ice cream machine turn it on about ten minutes before churning. Other wise take your freezer bowl out of the fridge right before churning (see notes for how to make ice cream without an ice cream machine).
Churn the ice cream. Transfer to pre chilled container and freeze for about four hours, or until firm.
To serve remove from the freezer, scoop and enjoy!