2 teaspoons vegetable oil 8 unpeeled red or white potatoes, cut into cubes 1 red onion, chopped 1/2 cup unsalted butter, sliced 1/2 cup swiss cheese, grated 1/4 cup parmesan cheese, grated 1/2 teaspoon garlic powder 1/2 teaspoon salt 1/4 teaspoon fresh ground pepper
Rub oil over a large sheet of heavy foil. Place all remaining ingredients in center of foil; tossing to coat. Fold and seal foil to make a large packet. Double wrap with another piece of foil.
Prepare a grill and grill over medium coals for about 25 minutes per side.