Line a 1kg loaf tin with a double layer of clingfilm. Put the apricots and apple juice into a small pan and add ½ the sugar. Heat gently until the sugar has dissolved. Partly cover the pan with a lid, then simmer for 10 minutes or so, until the apricots are tender and bathed in syrup (the exact time will depend on how ripe the apricots are, but cook them for at least 5 minutes, or the fruit will turn brown in the freezer.) Scoop about 8 of the apricot halves out of the pan and keep to one side. Purée the rest of the apricots and syrup with a hand blender and leave to cool.