4 medium potatoes, peeled and cut into 1 inch cubes
1 large red onion, cut into 1 inch cubes
1 (8 ounce) package sliced mushrooms
1 (1 ounce) envelope dry onion soup mix
1/4 cup butter, melted
Preheat an outdoor grill for medium heat.
Toss together the potatoes, onion, mushroom, and soup mix in a large bowl. Drizzle in the butter, and toss to coat. Divide into 4 portions, and seal each portion well in several layers of aluminum foil.
Cook potatoes on preheated grill until tender, 30 to 40 minutes. Turn at least once during cooking to ensure that they cook evenly.