Preheat the oven to 180 degrees celcius.
Chop the softened butter up into little bits and put them in the mixer.
Add the caster sugar.
Beat until the butter and sugar is light and creamy.
Crack the egg into a small bowl.
Measure out 1 teaspoon of vanilla essence.
Add the egg and vanilla to the mixer.
Sift the self raising flour and the plain flour together.
Measure out the coconut.
With the mixer on low, slowly add the flour and coconut until it forms a dough. You'll have to mix it with your hands at the end as it gets quite dry.
Roll into small balls and place on a tray lined with baking paper.
Flatten them a bit with a fork.
Bake for 12-15 minutes. Then cool on a wire rack.
To make the filling place 100g of softened butter into the mixer.
Sift the icing sugar to remove lumps.
On low speed cream the butter together with the icing sugar and vanilla essence.
It will become very thick.
So add a splash of milk until it's a good spreading consistency. Don't make it too runny!
Measure out about 3 tablespoons of jam.
Spread the icing onto one biscuit and the jam onto another biscuit then sandwich them together.