Combine one-third of the Peppadews, half of the parsley, the rosemary, 1 teaspoon salt and a few grinds of pepper in a bowl; rub all over the pork. Set aside while you prepare the potatoes.
Combine the potatoes and 1/4 cup water in a large microwave-safe bowl. Cover with plastic wrap and pierce a few times with a knife to vent; microwave until tender, about 8 minutes.
Heat a large skillet over medium-high heat; add the olive oil. Working in batches, add the pork and cook until browned, 1 1/2 minutes. Flip and cook until browned on the other side, 30 seconds; transfer to a plate.
Add the onion, mushrooms, tomatoes and garlic to the skillet; cover and cook, stirring occasionally, until the vegetables start browning, 8 minutes. Add the broth and the remaining Peppadews and brine. Bring to a simmer; cook until the sauce is slightly reduced, about 5 minutes. Return the pork to the pan and cook, flipping occasionally, until cooked through, 5 minutes; stir in the potatoes. Top with the remaining parsley.