Step 1

Preheat a gas or charcoal grill over medium high heat.

Step 2

Add the halloumi, onion, zucchini, peppers, potatoes, olive oil, basil, parsley, rosemary, garlic, salt and pepper to a large bowl and mix until well combined.

Step 3

Cut out 4 (about 18-inch) long rectangles of aluminum foil. Place two of the sheets on a work surface, then top each with an additional piece of foil (so they are double lined).

Step 4

Divide the vegetable mixture evenly between the foil pieces and spread in a thick layer, leaving a 2- to 3-inch border around the edges. Cut out 2 slightly smaller pieces of foil and place over the veggies. Tightly roll up / pinch together the edges around all sides so the packets are well sealed.

Step 5

Place the packets directly on the heated grill and cook for 15 to 20 minutes. Carefully open the packets - there will be quite a bit of steam. Sprinkle the tops of the veggies with the walnuts and season with additional salt / pepper to taste if needed.