Place the basil seeds in a cup of water and let it soak for about two minutes and drain.
Wash the soursop to remove any dirt.
Peel the fruit and set in a large mixing bowl.
Add one cup of water to the fruit in the mixing bowl.
Using a disposable hand glove, squeeze the fruit in the water and remove all the seeds.
At this point, you can either blend the soursop to get it's pulp or just use your hand to mash it up.
I prefer to use my hands as we loved the yummy soursop bits. If you prefer yours to be smooth, do give it a blend in the food processor.
In a pitcher, combine the soursop pulp, syrup, cold water, drained basil seeds and ice.
This is best served chilled.