Boil, steam or microwave potato until tender; drain. Mash potato in large bowl; cover to keep warm.
Meanwhile, boil, steam or microwave spinach until just wilted; drain. When cool enough to handle, squeeze excess liquid from spinach. Combine in medium bowl with cheese.
Melt butter in medium saucepan, add the water and salt; bring to the boil. Remove from heat; immediately stir in flour. Using a wooden spoon, beat until mixture forms a smooth ball. Beat in eggs and potato until smooth.
Using floured hands, roll level tablespoons of dough into balls; use finger to press hole into centre of each ball. Fill holes with level teaspoons of spinach mixture; roll potato balls gently to enclose filling.
Heat oil in large saucepan; deep-fry balls, in batches, until browned lightly. Drain on absorbent paper.
You could also use lasoda or pink-eye potatoes for this recipe, if preferred.Note