Fill a large pot or container with warm water. Using your immersion circulator, preheat the water bath to 140 F degrees (for medium, see chart for options from rare to well-done).
Season the pork tenderloin very liberally with kosher salt and freshly ground black pepper and place in a vacuum seal bag* along with the thyme, garlic, and shallot. Seal the bag(s) and place in water bath for at least 1 hour. You can leave the pork up to 4 hours.
Remove the bag from the water bath and remove the pork from the bag. Reserve the liquid but discard the aromatics. Pat dry the tenderloin with paper towels.
In a cast iron, or heavy bottom skillet heat the olive oil. Cook the pork, turning occasionally, until browned on most sides, about 2 to 3 minutes total.
1 tablespoon olive oil
Move the pork to a cutting board to rest.
Return same skillet to the stove over medium heat. Add wine and mustard. Mix well, scraping the bottom of the pan to mix in the golden crusty bits. Simmer for 30 seconds. Stir in the heavy cream, thyme and parsley. Simmer until sauce coats the back of a spoon.
¼ cup white wine, ¼ cup heavy cream, 2 tablespoon Dijon mustard, 2 teaspoon fresh thyme, Kosher salt and pepper, 2 teaspoon fresh parsley
Slice pork diagonally into ½" slices and serve with sauce.
Pork tenderloins typically serve 2 to 3 people. You can add two tenderloins to the same bag to serve 4 or more people.
See post for details on how to use a freezer bag and do the water displacement method in lieu of a vacuum sealer.
See post for cooking options from medium rare to well done.
For frozen pork tenderloin cook for a minimum of 2 hours.