Okay, this one is not for the faint-hearted. You can use
pre-bought choux puffs if desired.
To decorate:crystallised violets, fresh violets or other edible flowersTo serve:crème fraîche or double creamChocolate pastry cream500 ml (2 cups) pouring cream500 ml (2 cups) milk220 gm (1 cup) caster sugar10egg yolks75 gm (½ cup) cornflour2 tspvanilla extract180 gmdark chocolate (64% cocoa solids), melted125 gmunsalted butter, chilled and cut into small pieces, plus extra for greasingChocolate choux pastry675 gm (4½ cups) plain flour50 gm (½ cup) Dutch-process cocoa powder380 gmunsalted butter, cut into small pieces110 gm (½ cup) caster sugar20 eggsCaramel660 gm (3 cups) white sugar60 ml (¼ cup) light corn syrup
For chocolate pastry cream, combine cream, milk, half the sugar and ½ tsp salt in a saucepan and bring to the simmer over medium heat. Whisk egg yolks in a bowl with remaining sugar until sugar dissolves. Whisk in cornflour. Gradually pour cream mixture over egg yolk mixture and whisk to combine. Return mixture to a clean pan and cook over medium heat, stirring continuously, for 2 minutes or until thick. Remove from heat and whisk in vanilla and butter one piece at a time, then whisk in melted chocolate until combined. Pass mixture through a fine sieve into a bowl, cover closely with plastic wrap and refrigerate for 2 hours or until mixture is chilled and firm.
For chocolate choux pastry, preheat oven to 200C. Lightly grease four 45cm x 28cm baking trays and set aside. Sift flour and cocoa together into a bowl. Combine 1 litre water, butter and 3 tsp salt in a large saucepan over medium heat and bring to the simmer. Remove from heat, add flour mixture and cook stirring with a wooden spoon until mixture is smooth and pulls away from sides of pan and dough forms a ball. Return pan to stove and cook stirring over low heat for 1-2 minutes or until warmed through. Remove from heat, cool slightly and then transfer dough to bowl of an electric mixer fitted with a paddle attachment. Beat in sugar and 6 eggs. Add 12 more eggs, one at a time, mixing well after each addition. Spoon batter into a piping bag fitted with a 1.25cm nozzle. Cover remaining batter with a damp cloth or plastic wrap to prevent a skin from forming. Pipe batter into 2.5cm-wide and 2cm-high mounds onto prepared baking trays, spaced about 4cm apart. Beat remaining eggs together and use to lightly brush mounds. Bake for 20-35 minutes in batches or until firm and sound hollow when tapped. Transfer choux puffs to wire racks, and cool completely. Using the tip of a sharp knife, make a small hole in the bottom of each puff.
Using an electric mixer, whisk pastry cream until smooth. Spoon pastry cream into a piping bag fitted with a 1.25cm nozzle. Insert nozzle into hole of each choux puff and pipe in enough cream to fill. Set aside.
For caramel, combine 1½ cups water, sugar and corn syrup in a large heavy-based saucepan and bring to the boil over high heat without stirring. Cook for 20-25 minutes or until mixture reaches 155C (hard-crack stage) on a sugar thermometer. Remove immediately from heat.
Lightly grease a 25cm serving platter. Place a 26cm x 46cm croquembouche mould (see note) in middle of serving platter. Use tongs or insert a sharp knife into top of each choux puff and dip bottom half of each puff into caramel. Arrange a ring of choux puffs around the bottom of croquembouche mould. Using caramel to attach, layer with remaining choux puffs until mould is completely covered. If caramel gets too thick, return pan to a low heat to thin the caramel. Dip a fork into remaining caramel and swirl around croquembouche for a spun sugar effect. Carefully unmould croquembouche and return in upright position to the platter. Decorate with crystallised and fresh violets. Serve with crème fraîche or double cream.
Note Croquembouche moulds, crystallised violets
and edible flowers are available from speciality cake