Preheat the oven to 210°C (fan-assist). Judge heat according to your own experience - every oven is different.
Fill a cup with cold water and a line a tray with baking paper.
Cut out four circles (approx. 9 cm diameter) of puff pastry.
Cut two smaller circles (approx. 7 cm diameter) out of two of the four circles. Place the two larger circles on the baking-paper lined tray, brush the edges with water and place the two outer rings on top.
Bake the vol-au-vents for approx. 20 minutes until golden brown.
The creamy cider and sage sauce
Slice the unpeeled apples in half. Slice one apple-half lengthwise and chop into 2-3 cm pieces.
Slice the sage into thin strips.
Roughly chop the herbs to be used for garnish.
Half the peeled onion and slice into fine rings.
Melt the butter in a hot frying pan and sauté the onions until translucent.
When the onions are slightly translucent, sprinkle with the raw cane sugar, combine well and add half of the sage strips. Combine well once again, caramelise briefly, and then transfer half of the onion, sugar and sage mixture to a small bowl. In the frying pan, deglaze the remainder with cider and add the apple pieces. Simmer until the apple is softened but still firm to the bite.
Now add the cream, the remaining sage strips and the grated hard cheese. Stir well and simmer until the sauce is slightly creamy. Set the frying pan to one side; the sauce will thicken up as it sits. If required, add a little more cream later, and season with salt and pepper to taste.
Arrange the vol-au-vents on a plate.
Fill with the sauce.
Garnish with the remainder of the caramelised onions and the fresh herbs.