Sautee mushrooms and shallots.
Pound pork loin with a meat mallet.
Brush pork with dijon mustard, season with salt and pepper on both sides, and sprinkle with dried sage.
Spoon the mushroom mixture onto each pork paillard.
Roll pork tightly and secure with butcher's twine.
Sear pork roulades. Set aside.
In the same pan, roast the carrots, onions, and celery.
Add tomato paste and continue roasting for a minute.
Deglaze the pan with red wine. Reduce.
Tip contents of pan to the slow cooker.
Add pork and stock.
Braise for 6 hours on low.
Reduce braising liquid over the stove.
Whisk in cold butter nuggets.
Finish the sauce with truffle oil.