Red Potato-Rosemary Hobo Packs

10-12 medium sized red potatoes; dice these if they are large
1 small yellow onion, minced
2 cloves garlic, minced
2 Tbsp rosemary, chopped
2 Tbsp butter
Salt and pepper to taste

Using heavy duty aluminum foil, make an envelope large enough to include all ingredients and 25 percent extra room. Cook on grill or directly on a campfire. Check frequently. Serves 6-8.