1. Preheat oven to 140C. Mix the ricotta with the sugar, eggs, marsala and zest.
2. Stir in the flour. In a heavy based saucepan, pour in enough oil to reach 5cm.
3. Line a plate with kitchen paper and put in the oven. Heat the oil to 180C - check by using a thermometer or dropping a cube of bread into the oil; if it becomes crisp after 1 minute without turning brown, perfect.
4. Drop spoonfuls of the mixture into the oil, being careful not to overcrowd. Turn over with a spoon when necessary. When puffed and golden, transfer to the plate in the oven.
5. Mix the icing sugar with the cinnamon. Sprinkle the warm fritters with the sugar before eating.