Dacquoise noisette
- 120 g egg whites
- 100 g sugar
- 100 g hazelnut powder
- 20 g plain flour
- 80 g icing sugar
Praliné croustillant
- 200 g praline noisette
- 100 g milk chocolate, melted
- 80 g feuilletine (pailleté feuilletine)
Mousse au chocolat noir
- 250 g dark chocolate (70%)
- 100 g whole milk
- 4 egg yolks
- 40 g sugar
- 400 g whipping cream
The Trianon is an entremets built entirely on texture contrasts: crunchy dacquoise base, brittle praline croustillant, and the lightest possible chocolate mousse on top. All three layers must be at different temperatures when assembled — the dacquoise at room temperature, the croustillant set but not frozen, the mousse freshly made and just beginning to thicken. Assemble in a metal frame on parchment, and freeze overnight.
Method
Dacquoise
- Sift hazelnut powder with flour and icing sugar. Set aside.
- Whip egg whites to soft peaks. Add sugar gradually and whip to a firm, glossy meringue.
- Fold in the dry ingredients gently — do not deflate. Spread in the frame or pipe into a 24cm disc on parchment.
- Bake at 170°C for 18–20 min until golden and crisp on the outside. Cool completely.
Praliné croustillant
- Melt milk chocolate. Mix with praline noisette until smooth.
- Fold in feuilletine — the mixture should be thick and crumbly.
- Spread in a thin, even layer directly onto the cooled dacquoise. Press lightly to adhere. Refrigerate until set (~20 min).
Feuilletine is crushed crêpes dentelles. Cornflake crumbs are a workable substitute but less delicate.
Mousse au chocolat
- Make a pâte à bombe: whisk egg yolks with sugar over a bain-marie until pale and thick. The mixture should ribbon when lifted.
- Melt chocolate. Heat milk to ~60°C. Pour over chocolate in a thin stream, mixing from the centre. The ganache should be smooth and about 45°C.
- Fold the warm ganache into the pâte à bombe.
- Whip cream to soft peaks — not firm. Fold into the chocolate mixture in two additions. The mousse should be light, airy, and flowing but not liquid.
Assembly
- Place the dacquoise (with croustillant facing up) in the 24cm metal frame, set on parchment on a flat tray.
- Pour the mousse over the croustillant layer. Smooth the top flush with the frame.
- Freeze overnight or at least 4 hours until completely set.
- Remove from the freezer 20–30 min before serving. Run a warm knife or heat gun around the frame to unmould cleanly. Transfer to the serving plate.
- Dust the top with cocoa powder through a fine mesh. Add decoration if desired.
Background
The Trianon (also called the Royal) is a textbook entremets — it teaches the three fundamental layers of French mousse cakes: biscuit, croustillant, mousse. The dacquoise stays crisp because it is protected from the mousse by the croustillant layer — without it, moisture from the mousse would make the dacquoise soggy within hours.
The pâte à bombe base (egg yolks cooked over a bain-marie with sugar) is what gives the mousse structure and stability. It is a safer base than raw yolks and gives a richer, more emulsified texture than a simple anglaise or gelatine-set mousse. The mousse should not be over-whipped before assembly — it will continue to set in the freezer.
The freeze is essential for clean unmoulding. A refrigerated-only Trianon will not hold its shape when the frame is removed. The freeze also makes the mousse firmer and allows a clean slice. Serve partially thawed — too cold and the mousse has no flavour; fully thawed and it starts to lose the feathery texture.
Mistakes I've Made
- Mousse too warm when poured. It melts the croustillant and bleeds through. The mousse must be starting to set before pouring.
- Croustillant too thick. Impossible to slice cleanly — the feuilletine shatters and the layers separate. Spread thin.
- Unmoulding while frozen solid. The outer edge tears. Let it temper 20–30 min first, then warm the frame.
- Whipping cream to firm peaks. The mousse is too dense and loses its lightness. Soft peaks only — the mousse should fall off the spatula.
Sources
- Trianon Royal —