Coffee Cream Horn with Dark Chocolate Ganache

STEP 1: MAKE THE ROUGH PUFF PASTRY

Sift the flour and salt into a bowl. Add the very cold cubed butter and toss to coat, keeping the cubes intact — you want visible pieces of butter, not a rubbed-in crumb. Make a well, add the lemon juice and most of the iced water, and bring together with a bench scraper into a shaggy, streaky dough, adding the last of the water only if needed. Shape into a rough rectangle, wrap and chill 20 minutes. On a floured surface, roll into a long rectangle, fold in three (a single turn), give it a quarter turn, and roll out again. Repeat for five turns in total, chilling 20 minutes whenever the dough or butter starts to soften. Keep everything cold: if the butter warms it melts into the dough instead of forming layers, and you lose the flake. Wrap and chill the finished block at least 30 minutes.

STEP 2: MAKE THE COFFEE CRÈME PÂTISSIÈRE

Warm the milk with the instant espresso powder until hot but not boiling, stirring to dissolve. In a bowl, whisk the egg yolks, sugar and cornflour to a smooth paste. Pour the hot coffee milk over the yolks in a steady stream, whisking constantly, then return to the pan. Cook over medium heat, whisking hard, until it thickens and just reaches a boil; let it bubble for a full minute to cook out the cornflour, or it will taste raw and may weep later. Off the heat, whisk in the vanilla and butter. If using powdered gelatine, bloom it in cold water, then stir into the hot custard until dissolved. Press cling film onto the surface and chill until cold and set.

STEP 3: MAKE THE DARK CHOCOLATE GANACHE CENTRE

Place the finely chopped dark chocolate in a bowl. Heat the cream until it just begins to simmer, pour it over the chocolate, and leave for one minute before stirring from the centre outwards to a smooth, glossy emulsion. Stir in the optional butter for shine. Let it cool to a thick, pipeable consistency — firm enough to hold its shape inside the horn but still soft enough to pipe. Rushing this is the usual cause of a runny centre.

STEP 4: SHAPE AND BAKE THE HORNS

Preheat the oven to 400°F (200°C). Lightly grease the cream horn moulds. Roll the chilled pastry to about 3 mm thick and cut long strips roughly 1 inch (2.5 cm) wide. Starting at the pointed tip of each mould, wind a strip around in a spiral, overlapping each turn by about half its width and finishing at the open end; don’t stretch the pastry or it will shrink back. Brush with egg wash, keeping the seam from touching the mould, and sprinkle lightly with sugar. Chill the shaped horns 15 minutes — cold pastry into a hot oven gives the best lift. Bake 18–22 minutes until deep golden and properly flaky. Cool a few minutes, then gently twist and slide each horn off its mould while still warm; cool completely on a rack.

STEP 5: FINISH THE COFFEE CRÈME DIPLOMAT

Whip the cold double cream to soft peaks. Loosen the chilled coffee pâtissière with a whisk until smooth, then fold in the whipped cream in two additions to a light, pipeable diplomat cream. Fold gently — overworking knocks out the air and risks the cream weeping inside the horn. Transfer to a piping bag fitted with a star nozzle.

STEP 6: FILL THE HORNS

Pipe a small plug of the dark chocolate ganache into the pointed tip and a little up the centre of each horn, so every bite reaches the chocolate core. Then pipe the coffee crème diplomat to fill the horn fully, finishing with a neat swirl proud of the open end. Fill close to serving — the crisp pastry softens once filled.

STEP 7: DECORATE AND SERVE

Dip or drizzle the open ends with melted dark chocolate and finish each horn with a chocolate-covered coffee bean. Serve soon after filling, while the lamination still shatters and the diplomat cream is cold and set.