1.Make lemon cream filling. Bring milk to the boil in a medium saucepan. Meanwhile, combine rind, egg yolks, sugar and cornflour in a medium heatproof bowl; gradually whisk in hot milk. Return custard to pan; stir over heat until mixture boils and thickens. Cover surface of custard with plastic wrap; cool 20 minutes. Refrigerate 3 hours, then fold in cream in two batches.
2.Preheat oven to 220°C/425°F. Grease oven trays.
3.To make choux pastry, combine the water, butter and sugar in a small saucepan; bring to the boil. Add flour; beat with a wooden spoon over medium heat until mixture comes away from base of pan. Transfer pastry to a medium bowl; beat in two of the eggs, one at a time. Whisk remaining egg with a fork, beat enough of the egg into the pastry until it becomes smooth and glossy but still holds its shape.
4.Drop level tablespoons of pastry, about 5cm (2 inches) apart, on trays.
5.Bake 10 minutes. Reduce oven temperature to 180°C/350°F; bake 15 minutes. Make a small cut into the base of each puff; bake a further 10 minutes or until puffs are dry. Cool on trays.
6.Make lemon icing. Sift icing sugar into a small heatproof bowl. Stir in enough lemon juice to make a stiff paste. Stir icing over a small saucepan of simmering water until spreadable.
7.Spoon filling into piping bag fitted with a 5mm (¼-inch) plain tube; pipe through cuts into puffs. Place puffs on a foil-covered tray; drizzle with lemon icing. Decorate with candied lemon strips, if you like.
To make candied lemon strips: remove the rind from one lemon using a zester. Drop the rind into a small saucepan of boiling water; drain. Do this two more times. Toss rind in a little caster (superfine) sugar; cool.Note