Peel the banana and cut into pieces. Halve the prickly pear lengthways and, like with a kiwi, remove the flesh with a spoon. Wash the currants and remove the berries from the stalk with a fork.
Put all ingredients in a blender and mix on the highest level for about 2 minutes. The prickly pear pits are unlikely to be completely ground up, so pits will be felt.