Salt and pepper pork, add thyme, rosemary to bag. Can be frozen for later.
Fine dice the shallot.
Sous vide pork at 140 for 2 hours (3 if frozen). It will come out looking a bit pink, this is ok.
Meanwhile, cook mushrooms. Deglaze with white wine and save the liquid. See below for mushroom technique.
Make Sauteed Mushrooms:
Preheat a large pan on medium.
Add mushrooms to the hot pan with no oil or butter, just by themselves. Salt them in the pan.
Cover the pan and cook until a good amount of water has been released by the mushrooms.
Uncover and cook off the water. Then add oil or butter, plus anything else you want (wine, garlic, onion, herbs, whatever).
Heat oil nice and hot in a cast iron pan. Preheat pan a bit first so it doesn't smoke. Dry and season pork. Sear pork on all sides. On the last side, add 2tbsp butter, and a bouquet of herbs, baste until fully seared. Set pork aside to rest. The herb bouquet stays in.
Deglaze pan again with wine. Toss in shallot and cook until softened. Add 2tbsp more butter as needed.
When shallot is soft, add cream and mushroom liquid. Simmer down to a nice sauce. Add in mushrooms and pork medallions to finish.