Preheat the oven to 160C.
Cream butter and sugar together and add the egg yolk, beating well to combine.
Add all the other ingredients – to form a stiff dough.
Press dough evenly into a greased loose bottomed fluted tart tin (28cm).
Spread the jam onto the pastry.
Whisk the egg whites until soft peak stage then gradually whisk in the castor sugar until thick and glossy.
Fold in the coconut and spoon on top of the jam.
Bake at 160˚C for 30 minutes or until golden brown.
Allow to cool in the tin before removing and dusting with icing sugar.