Heat the grill to medium.
Toss the sweet potatoes, peppers, onion, garlic, rosemary, oil, and a very generous pinch each of salt and pepper in a large bowl until evenly coated. Divide among four large sheets of heavy-duty foil. Wrap and seal the foil to form packets.
Grill the packets and the bratwurst, turning the bratwurst to evenly brown, until the vegetables are tender and the meat is cooked through, about 10 minutes.
Carefully open the packets and divide among serving plates. Top with the bratwurst, sliced if you'd like, and garnish with parsley.
Sponsor recipe courtesy of Eddie Jackson for Walmart