Bring your pork tenderloin out of the fridge and allow it to set on the counter for 20-30 minutes before preparing/cooking.
Preheat your oven to 400 degrees f.
Pat the tenderloin completely dry with a paper towel and place it in a baking dish.
Very lightly sea salt and pepper to taste.
In a large bowl, whisk together your homemade cranberry sauce, diced apple, vinegar, honey, melted butter, minced garlic, sea salt, and freshly ground black pepper until well combined.
Spoon this cranberry-apple mixture over the tenderloin to evenly coat.
Roast in your preheated oven, covered, for 35-45 minutes, or until the internal temperature reaches 145 degrees f. This will result in a roast that is both safe and at its best quality—juicy and tender.
Remove from the oven to rest, covered, for 10 minutes.
Slice against the grain, garnish with parsley and enjoy while hot!