In a saucepan, bring to a boil, the milk, butter, salt and lemon zest.
Add the flour all at once and mix vigorously with a wooden spoon until the mixture comes away from the sides and forms a ball.

Put the dough in the mixer bowl, and add the eggs one by one, mixing well between each addition.

Heat the oil in the deep fryer to 350 F (180 C).

In a large bowl, mix the powdered sugar and cinnamon. Set aside.

With wet hands, take some dough and shape it into a ball the size of a large nut (about the contents of a tablespoon).

Drop the balls of dough into the oil and fry for 5 to 7 minutes, turning occasionally, until they are golden brown.
Remove them with a slotted spoon and let them drain on paper towels.
Coat them in the sugar-cinnamon mixture.
To be enjoyed hot or cold.