Stack of Recipes Forums has a number of threads dedicated to feijoa recipes. They can be a bit hard to navigate around, with all the bump entries and such but are worth a good search for some recipe gems.
This jam is a microwaveable version and is popular with posters. Jam is on my ‘to-do list’ so if you give this a go, please let me know how it goes
FEIJOA & GINGER JAM
Ingredients
- 500g peeled feijoas
- 500g sugar
- juice of 1 lemon
- 3 tablespoons freshly grated ginger
- ½ cup water
Method
- Chop the peeled feijoas. Place in a food processor and pulp well.
- Place pulped feijoas in a large glass bowl with the sugar, lemon juice, fresh grated ginger and water.
Use a very large bowl or it overflows! - Microwave on high for 5 minutes, then stir.
- Cook for another 10 minutes, stirring once, then pour into jars and seal.
Be careful getting the bowl out of the microwave as it will be very hot.
FEIJOA FEIJOA 
I am terrible in the kitchen. Here is my favourite feijoa jam:
http://www.threewisemerchants.com.au/feijoa-ginger-jam/
Yes, we love Hinterland Feijoas too.
Very delicious jam and easy to make. Five or six large feijoas are 500 gm – too few to make a dent in the harvest. So I make a double recipe twice. Added no water at all. Used half a cup of preserved ginger (from the bulk bin, soaked for months in the pantry in brandy) per kilo of feijoa, and chopped it in the food processor with the feijoas. The initial mix is an unappetising beige-yellow. When it has boiled to a jam consistency, it turns a beautiful golden colour. The jam is quite tart so I bottled it with circles of baking paper dipped in brandy placed on the full jars before screwing the lids on. The fruit acid may rust the metal lids otherwise.