Place the blackberries, sugar, and water into a pot and bring to a boil. Cook the ingredients until they reach a thick, jam-like consistency.
Using the back of a spoon, press the mixture through a sieve, creating a thick blackberry syrup.
Pour some of the syrup into a large glass, followed by the ice cream and more syrup. Finally, fill the glass with sparkling water and watch the foamy goodness unfold!