Mix all the ingredients together to form a sticky dough.
Line a muffin tray or use tart cases. Use a tablespoon to get equal amounts of mixture from the bowl and use your hands or the back of a spoon to form mini tarts in each of the holders.
Bake for 15 minutes and then leave to cool and they will harden.
Chop the plums and add to a saucepan with the water and sweetener.
Bring to the boil and then simmer on a low heat for around 10 minutes until a sticky, chutney-style mixture is formed.
Spoon into the tart bases and leave to cool.
*Apple puree can be bought at the supermarket- I get mine from the kosher aisle in Tesco. You can also get it in some baby food aisles. Alternatively, simmer chopped apples in a little water and blend them to make your own.