01 - Preheat your campfire, grill, or oven to medium-high heat (400°F).
02 - In a mixing bowl, combine the ground beef with garlic powder, onion powder, smoked paprika, salt, and pepper. Mix gently just until combined, being careful not to overwork the meat.
03 - Divide the seasoned beef mixture into 4 equal portions.
04 - Tear 4 large sheets of heavy-duty aluminum foil (about 12 inches per side) and brush the center of each with olive oil to prevent sticking.
05 - Layer potato slices in the center of each foil sheet, followed by onion, bell pepper, and mushrooms. Season the vegetables lightly with salt and pepper.
06 - Press each portion of seasoned ground beef into a flat patty and place on top of the vegetables in each packet.
07 - Drizzle 1/2 tbsp ketchup and a small amount of mustard over each patty.
08 - Fold the foil up to form tightly sealed packets, ensuring they are completely closed to prevent any leaks during cooking.
09 - Place the sealed packets on the campfire grate, grill, or in the oven. Cook for 20 to 25 minutes, flipping once halfway through, until the beef is cooked through and the vegetables are tender.
10 - Carefully open each packet, watching for hot steam. Place a slice of cheddar cheese on each patty, then reseal the packets and cook for 2 more minutes until the cheese melts.
11 - Serve directly from the packets or transfer to plates. Garnish with sliced pickles, chopped lettuce, tomato slices, and extra condiments as desired.