Rub salt, pepper, and dried thyme into the tenderloin- in you preferred amounts. Set aside.
Add the chicken broth and cornstarch to a medium sized mixing bowl, whisking until evenly combined & the mixture's smooth. Stir in the mushroom soup, onion soup seasoning ,and apple cider until evenly combined. Set aside.
Add the olive oil to a dutch oven, and heat over medium high. When the oil's hot, sear the tenderloin on all sides. Watch it carefully to ensure it's seared, not burned.
When every side has a nice crisp, brown sear on it- pour the soup mixture into the pot over top of the pork.
Transfer the dutch oven to an oven heated to 425 degrees, and bake for 22-25 minutes, or until cooked through.
Remove the dutch oven from the oven. Transfer the tenderloin to a baking dish, loosely cover with foil, and let it rest for 10 minutes.
Whisk the gravy in the dutch oven to combine, and serve drizzled over slices of the tenderloin.