Spray the bottom of the crock pot generously with cooking spray to prevent sticking. Arrange the halved carrots and finely chopped celery evenly at the bottom. This vegetable layer will serve as the base for the pork and also add flavor to the dish.
Place the pork tenderloin directly on top of the vegetables in the crock pot. Make sure it sits evenly so it cooks properly on all sides.
In a separate bowl, combine the applesauce, water, Lipton Recipe Secrets Onion Soup Mix, salt, and ground black pepper. Stir well to form a savory and slightly sweet sauce. Pour this applesauce mixture evenly over the pork tenderloin, covering as much surface area as possible for maximum flavor. I like to give the pork a gentle rub with some of the sauce—this helps boost the taste even more!
Cover the crock pot with a lid and cook the pork on the LOW setting for 4 to 5 hours. After about 4 hours, check the pork for doneness—it should be tender and easy to slice. If not fully cooked, continue to cook for another hour. Cooking low and slow makes the pork juicy and allows the vegetables and sauce to meld together with rich flavor.
Once the pork is cooked through, serve it hot alongside the tender vegetables and the flavorful gravy created in the crock pot. To make the meal even more comforting, I like to spoon extra sauce over the pork just before serving.