I like to start my grill first so that it can get up to temperature. Then wash and thinly slice the red potatoes. Place them in the middle of the foil.

Thinly slice the onion and place it on top of the sliced potatoes. I like to have 3 parts potato per 1 part onion.

Pour the salad dressing over the top, and toss the potatoes around to evenly coat them in dressing.

Wrap the potatoes up in the foil. You want to do this methodically so that the salad dressing doesn't leak out. I recommend folding the right and left sides of the foil and sealing them up. Then fold the top and bottom together and seal them together creating a big square.

Place the foil wrapped potatoes on the grill. Let cook for 20 minutes, then carefully flip the potatoes. Some of the dressing might leak out when you flip the potatoes and when that happens the flame flares up - BE CAREFUL. Let cook for another 20 minutes.

Remove the foil packet from the grill. Place it in a baking dish, and unwrap the foil, exposing the top of the potatoes. Sprinkle parmesan over the top of the potatoes, and place them in the oven until the broiler. Let cook for 3-5 minutes until golden brown.