Halve and core the apricots and cut the halves apart again in the middle. Wash the orange, rub dry, finely grate the skin and squeeze out the juice. Put the apricots, orange juice, 1 teaspoon orange peel and the sugar in a pot and bring to the boil once. Simmer for 5 minutes. Remove the pan from the heat and stir in the vanilla. Allow to cool for a few minutes, pour into a jar and refrigerate until serving.