Make sure any sinew is removed from the loins as they will toughen up as the loins cook and become unpalatable.
Heat the olive oil to 65° degrees – it is probably a good idea to get a sugar/oil thermometer so you can make sure the oil maintains a constant 60° - 65°
Add the peppercorns, bay leaves, rosemary and thyme to the oil and let them steep whilst the oil heats up to allow them to flavour the oil then add the loins when the oil reaches 64° - 65°. Keep an eye on the temperature as when you add the loins the temp will drop and you will need to bring it back up to 60° and try and keep it there for the duration of the poaching.
At a constant 60° you cannot over cook the loins.
Poach for one and a half hours.
Toss the apple rings and fennel slices in a bowl with the brown sugar and toss them about to coat.
In a fry pan over medium heat add two tbls of butter and when foaming add the apple and fennel and caramelise.
Depending on the size of your fry pan you may need to do this in batches.
Use an apple that will stay intact when it is cooked such as a Granny Smith – you want the apple rings to still have a little bite to them and not turn to mush when you cook them.
Set aside and keep warm.
In the same pan as you caramelised the apples and fennel add in 2 tbls of butter and when foaming add in the wine and let cook for a 20 seconds then add in the cream.
Stir and simmer until reduce by half and then add in the mustard and the blue cheese.
Stir to combine and taste for seasoning and add some pepper.
When the sauce is ready toss the sorrel leaves through allowing them to wilt slightly.
Put the sorrel to one side of a plate then place two apple rings on the plate and some place the caramelised fennel on top.
Take the loins out of the oil and in a hot fry pan sear them very quickly on all sides.
This will caramelize the outside of the loins but do not take more than a few seconds on each side.
Season with salt and then place two loins on top of the apples and draping over the sorrel.
Drizzle the sauce over the loins and around the plate.