Peel the apples and cut them into pieces. Combine apples with prunes in a saucepan. Wash the lemon. Grate the zest and set aside. Squeeze the juice, add it to the pot with the water. Simmer for about 15 minutes covered.
Blend everything with a hand blender. Then pour through a fine sieve. Add the lemon zest and coconut syrup. Allow to cool.
Whisk the egg whites and mix. Pour into ice cream maker and make the sorbet.
Distribute the sorbet into glasses. Garnish and serve immediately.