Arrange potatoes on half of a lightly greased 30-inch length of heavy-duty aluminum foil. Top with onion; sprinkle with garlic, parsley, salt and pepper. Drizzle with reserved drippings; add butter, crumbled bacon and cheese. Fold aluminum foil loosely over potatoes; seal edges of packet tightly. Place on a baking sheet; bake at 350° for 30 to 35 minutes. Open carefully and check for doneness; return to oven for a few minutes longer, if necessary.