Prepare the lemon syrup a day in advance.
Wash the lemons, remove and julienne the rind. Then put the rind into a saucepan with water and sugar, leave to boil for 8-9 min. Cool and store in the refrigerator.
Prepare the coffee with the moka pot, heat the milk without boiling it, add the lemon syrup and emulsify with a blender.
Pour into a cappuccino cup, add the milk by placing the foam on first with a spoon, and savour without adding any sugar.