The Louis XV is the iconic signature dish of Alain Ducasse’s three-star Michelin restaurant in Monte-Carlo. The cake is a simple layered mousse cake but Ducasse’s perfect mastery over each individual component is what has made it such a celebrated dessert. The Louis XV dessert recipe teaches a number of simple classic French patisserie techniques, which come together to create something spectacular.

The base is a thin dacquois – a nut-based meringue, made from hazelnuts. A layer of feuilletine mixed with praline is spread on top to give a little chewy crunch. Feuilletine are fine cornflake-like crispy flakes, which are tough to make, and easiest bought. Praline paste is made from finely ground caramelised hazelnuts. We’ve opted to make our own praline recipe from pure hazelnut paste stirred through with caramel, as it gives a depth of hazelnut flavour which can be hard to find in industrial, over-sweetened pralines. It is very difficult to grind nuts finely enough at home, which is why we start with the already smooth hazelnut paste.

Next comes the chocolate mousse, the body of the cake. The chocolate mousse recipe uses the sabayon technique – whisking warm egg yolks together with a sugar syrup until pale, silky, and with a ‘ribbon consistency.’ And, finally the cake is finished with a dark chocolate glaze. The glaze is poured over the Louis XV, and reflects like the surface of a mirror. The dark chocolate glaze recipe is one to have up your sleeve for many other cakes – one day you may even find yourself needing to ice a sachertorte on the Great British Bake Off.

The Louis XV dessert is not for the faint-hearted, but take the time to work through each step, and you’ll finish with an education in French patisserie, and a delicious show-stopper! We will often make twice as many as we need up to the end of the “chocolate mousse stage”, and keep them in the freezer for a quick luxurious dessert, another day. The chocolate glaze should really be made and applied the day the dessert is served – the finished dessert will keep for up to half a day in the fridge.

louis xv mousse Louis XV Dessert Recipe

Louis XV Recipe
Serves 8

For the hazelnut dacquois
170g egg whites
50g caster sugar
120g icing sugar
100g hazelnuts
25g plain flour, sifted

For the feuilletine praline layer
70g hazelnut paste
70g caster sugar
60ml double cream
40g white chocolate couverture
80g feuilletine

For the chocolate mousse
75g egg yolks
30g water
25g caster sugar
10g glucose syrup or light corn syrup
135g dark chocolate couverture (70%)
270g double cream

For the chocolate glaze
150g dark couverture chocolate (70%)
170ml double cream
90g caster sugar
10ml water
35g cocoa powder

To serve
8 hazelnuts (approx 25g)
Edible gold leaf sheets

Equipment
8 Square mousse rings 60x60x35mm (or 8 circular mousse rings 70mm x 35mm)
Chef’s blowtorch
Sugar thermometer (we use the Superfast Thermapen Thermometer)

To make the dacquois

  1. Dehydrate the hazelnuts in the oven at 150°C for 15 minutes.
  2. Allow the hazelnuts to cool and then blitz them into a powder in a food processor. Be careful not to over blend the hazelnuts or they will turn into a paste.
  3. Turn the oven up to 180°C and cover a baking tray in baking paper.
  4. Whisk the egg whites to stiff peaks and add the caster sugar to stabilise them.
  5. Sieve together the icing sugar, hazelnut powder and the flour.
  6. Incorporate the meringue into the powders gently, using a spatula.
  7. Pipe the dacquois on the baking paper so you have a whole baking tray of dacquois.
  8. Cook at 180°C for 12-15 minutes. Transfer to a cooling rack.
  9. When  cool, use mousse rings to cut out shapes to form the base of the Louis XV dessert.

To make the praline-feuilletine layer

  1. Begin by making the praline. Heat the caster sugar in a pan until it turns into a light brown caramel. Deglaze the pan with double cream and pour into a bowl with the hazelnut paste. Mix well.
  2. Melt the white chocolate couverture in a bain marie. Add the feuilletine and melted white chocolate couverture to the praline mixture, and stir together.
  3. Using a teaspoon, spread a thin layer of the mixture onto the dacquois base inside the mousse rings.

To make the chocolate mousse

  1. Make a sugar syrup. Add the water, sugar and corn syrup to a pan, and bring to the boil. Leave to one side to cool.
  2. Place the egg yolks and the cooled syrup in a stand mixer bowl. Heat over the hob on a low flame until the mixture reaches 55°C, whisking constantly.
  3. Transfer to the stand mixer and whisk until the mixture cools and begins to take on a ‘ribbon consistency.’
  4. Melt the chocolate in a bain marie, and gently stir into the fluffy egg and sugar mixture.
  5. In a separate bowl whisk the cream into medium peaks and fold it in.
  6. Spoon into the mousse rings, and scrape across the surface to flatten with a metal spatula. Place in the freezer.

To make the chocolate glaze

  1. Before making the chocolate glaze remove the mousse rings from the mousse. First transfer the mousse rings to a cooling rack. Use a chef’s blowtorch around the edges until you can pull off the mousse ring leaving the mousse intact. Return to the freezer.
  2. To make the chocolate glaze, place the chocolate in a mixing bowl. Bring approximately 2/3 of the cream to the boil and pour over the chocolate. Mix well, until well incorporated. This is a ganache.
  3. Bring the remaining 1/3 of the cream to the boil with the water and the sugar. Add the cocoa powder and return to the boil. Pour over the ganache.
  4. The glaze should be liquid and runny. If it’s too thick it will set too thick. If this is the case just gently heat it over a bain marie to make it less viscous.
  5. Remove the chocolate mousse from the freezer, and place the cooling rack over a roasting tin, to catch any glaze that drips through. Pour the glaze over the frozen chocolate mousse making sure to cover all sides. Place in the fridge for at least 1 hour. Any glaze that has dripped through can be collected, warmed and used again the next day if needed.

To serve

  1. Transfer the Louis XV from the cooling rack to a plate, using a spatula.
  2. Top with a hazelnut and apply a little gold leaf using chef’s plating tweezers.

louis xv blue Louis XV Dessert Recipe