Preheat the oven to 210C/410F/Gas 7.
Season the pork fillet and brush with honey.
Heat a frying pan until hot and add the butter. When foaming, add the pork. Sear on each side until golden brown.
Place in the oven and cook for 8-10 minutes until just cooked through - juices will run clear when pierced when the pork is cooked.
Remove from the oven and rest for five minutes.
To make the rösti, grate the potatoes and apple on a large grater into a tea towel.
Twist the tea towel around and squeeze out any water and starch.
Place the dry potato mix into a bowl and add the créme fraîche and egg yolks.
Season with salt and freshly ground black pepper.
Fill a 8cm/3in chefs' ring halfway with the potato mix. Place a prune on top.
Fill to the top with the remaining potato mix and press down firmly.
Heat a frying pan until hot and add the butter. Place the rösti into the pan. Remove the ring and cook the rösti for 2-3 minutes on either side until golden brown and crisp.
Serve the rösti with the sliced pork fillet.
