2. In a zip-top bag add the orange juice, mustard, 1 teaspoon salt, 1/2 teaspoon pepper, and 1 tablespoon Tuscan seasoning. Seal and shake to combine. Add in the pork tenderloins. Seal and refrigerate for at least 30 minutes and up to 3 hours.
3. Meanwhile, add the potatoes, remaining teaspoon of salt, 1/2 teaspoon black pepper, 2 teaspoons Tuscan seasoning and olive oil to a rimmed sheet pan. Toss to coat. Roast for 30 minutes or until just tender.
4. Reduce heat to 350ºF.
5. Remove tenderloins from marinade. Discard the marinade. Arrange the tenderloins on top or between the potatoes. Return to oven and roast for 20-25 minutes or until the internal temperature of the pork is 145°F.
6. Set oven to broil. Broil pork for 3-4 minutes or until it is brown and crusty. Rest 5 minutes before slicing.