1.Make coffee pastry cream; Bring milk and coffee to the boil in a medium saucepan. Meanwhile, whisk egg yolks, sugar and cornflour in a medium heatproof bowl; gradually whisk in hot coffee mixture. Return mixture to pan; stir over high heat until mixture boils and thickens. Remove from heat; whisk in butter. Transfer pastry cream to a medium bowl; cover surface with plastic wrap, refrigerate 2 hours.
2.Preheat oven to 200°C/400°F. Grease two oven trays, set aside.
3.To make choux pastry, combine water, butter and sugar in a medium 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 eggs, one at a time, until pastry becomes smooth and glossy but still holds its shape.
4.Spoon pastry into piping bag fitted with a 1.5 cm (¾-inch) plain tube; pipe eight 5.5cm (2-inch) balls, about 5cm (2 inches) apart, onto one tray. Pipe eight 4cm (1½-inch) balls, about 5cm apart, on remaining tray.
5.Bake puffs 20 minutes; remove smaller puffs, cool on wire rack. Bake larger puffs a further 5 minutes; cool on wire rack. Cut a small opening into the base of each puff.
6.Meanwhile, make coffee glaze; sift icing sugar into a small heatproof bowl; stir in enough coffee to make a thick paste. Place bowl over a small saucepan of simmering water; stir until mixture is smooth.
7.Spoon coffee pastry cream into piping bag fitted with a 1.5cm (¾-inch) plain tube; pipe pastry cream through cuts into puffs.
8.Spread top of one small puff with glaze. Spread top of a large puff with glaze; before the glaze sets, position small puff on top of large puff. Repeat with remaining puffs and glaze.
9.Meanwhile, beat cream in a medium bowl with an electric mixer until firm peaks form. Spoon cream into a piping bag fitted with a 5mm (¼-inch) fluted tube; pipe cream around centre to decorate.
The ‘religieuse’ is meant to resemble a nun in a habit.Note