Place the pork tenderloins in a Ziploc bag. Set aside.

In a small bowl, whisk together the apple cider vinegar, soy sauce, Dijon mustard, honey, olive oil, lemon juice, garlic, paprika, and crushed red pepper flakes.

Pour the marinade over the pork. Seal the bag and make sure the pork is well coated. Place in the refrigerator and let the pork marinate for 30 minutes or for up to 24 hours.

When ready to cook, preheat the oven to 425 degrees F. Line a large rimmed baking sheet with parchment paper or aluminum foil. Set aside.

Remove the tenderloins from the bag and place in the center of the sheet pan, not touching. Discard the marinade.

Place the potatoes in a medium bowl and drizzle with olive oil. Add the garlic powder, Italian seasoning, salt, and pepper. Toss until potatoes are well coated.

Arrange the potatoes around the pork tenderloins in an even layer. Place the pan in the oven and roast for 20 to 25 minutes, or until tenderloin is cooked through and reaches an internal temperature of 145 degrees F.

Remove the pan from the oven and transfer the tenderloins to a cutting board. Tent with aluminum foil to keep warm while the pork rests. Toss the potatoes and return to the oven to cook for an additional 5 to 10 minutes or until potatoes are tender and crispy. Remove from the oven.

Use a sharp knife to cut the pork into 1/2-inch-thick slices. Garnish with parsley and serve warm with potatoes.