For the whipped vanilla ganache:
- 130g Isigny Sainte-Mère Cream & Calvados
- 130g whipping cream (30% fat)
- 10g acacia honey
- 140g white chocolate
For the diced apple:
- 1 Chantecler apple
- 1 knob of salted butter
For the white chocolate shards:
- 100g white chocolate
- 1/2 vanilla pod
For the hazelnuts for decoration:
- 7 hazelnuts
- 50g sugar
For the syrup:
- 60g water
- 5 g sugar
- 1/2 vanilla pod
For the Viennese sponge:
- 45g egg yolks (2 egg yolks)
- 75g eggs (1¼ eggs)
- 75 g sugar
- 90g egg whites (3 egg whites)
- 50 g T55-type flour
Preparation the day before:
Heat 130g of Isigny Sainte-Mère Cream & Calvados together with the honey. While it is heating, melt the white chocolate in a bain-marie.
Pour the hot Isigny Sainte-Mère Cream & Calvados in three goes onto the melted chocolate, mixing with a spatula each time.
Add the cold whipping cream and mix together.
Cover with cling film and leave the ganache to chill overnight in the refrigerator.
Peel and dice the apple.
In a hot pan, melt the butter and brown the diced apples until they are soft.
Place them in a container and chill until the next day in the refrigerator.
For the syrup:
Heat the water together with the vanilla seeds and sugar. Once the syrup is hot, remove from the heat, cover and chill in the refrigerator until you are ready to assemble the roulade is ready to be assembled.
White chocolate shards:
Gently melt the white chocolate in a bain-marie with the seeds of half a vanilla pod. The chocolate should be nice and smooth.
Spread a thin layer of the white chocolate onto a sheet of baking paper. Allow to cool until the chocolate hardens. Once cooled, break the chocolate into small shards with your fingers.
Store in an airtight container at room temperature until the roulade is ready to be assembled.
On the day:
Preheat your oven to 170°C fan.
Whisk together the yolks, eggs and 50g of sugar.
Beat the egg whites to stiff peaks with an electric mixer and gradually add the remaining 25g of sugar.
Pour half of the beaten egg whites into that first egg mixture. Gently fold the mixture using a spatula.
Add the rest of the egg whites and the flour and fold again gently.
Spread the mixture onto a tray covered with baking paper to obtain a rectangle of about 30cm by 40cm.
Bake for about 12 minutes at 170°C.
Allow the sponge to cool before removing it from the baking tray.
If necessary, trim the edges slightly to form a tidy rectangle shape.
Turn the sponge out onto a large sheet of baking paper. The side of the sponge that was in contact with the baking sheet should be on top.
Using a pastry brush, brush the sponge with the syrup.
To fill the roulade:
Whip the ganache in a mixer until it reaches the consistency of whipped cream.
Set aside three large tablespoons of the whipped ganache to cover the roulade.
Spread the whipped ganache over the sponge, leaving a 2cm gap without ganache on one of its sides. Add the diced apples.
Carefully roll up the roulade using the baking paper.
Slide it into place in the middle of the baking paper, with the open edge of the sponge on the bottom.
Roll up the roulade in baking paper and press tightly so that the roulade to get a nice round shape.
Chill the roulade in the refrigerator for an hour without removing the baking paper so that the whipped ganache can set.
Hazelnuts for decoration:
Pour 50g of sugar into a saucepan and heat over a medium heat. The sugar will gradually melt and turn into a thick syrup. As soon as the caramel turns an amber colour, lower the heat to its minimum setting and dip the hazelnuts into the caramel one at a time to cover them. Leave to cool on a sheet of baking paper.