1. In a small bowl, create the rub for the pork roast by combining the dried parsley, garlic powder, paprika, salt, crushed red pepper flakes and oil. Massage the rub all over the pork roast until all sides are covered. Cover and place the pork roast in the fridge for at least an hour.
2. Dice the potatoes into 1″ pieces and on a large baking sheet, toss the potatoes and mushrooms together with the oil.
3. Preheat the oven to 400 F. Place the roast in the middle of the baking sheet along with the potatoes and mushrooms, and place in the oven to roast until it has reached a minimum internal temperature of 145 F.
4. While the pork is cooking, prepare the chimichurri sauce: In a food processor, combine the parsley, cilantro, roasted garlic and oil until a coarse sauce forms. Add the vinegar and crushed red pepper flakes and blend together until you’ve reached the texture you desire.
5. Remove the roast from the oven, slice and serve with chimichurri sauce.

Leftover chimichurri sauce will keep in the fridge, in an airtight container for 3-4 days.