01 - Build a campfire with established coals, preheat a grill, or set an oven to 400°F for medium-high heat.
02 - In a mixing bowl, combine the ground beef with garlic powder, onion powder, smoked paprika, salt, and black pepper. Mix gently until just incorporated, being careful not to overwork the meat.
03 - Divide the seasoned beef mixture into 4 equal portions and shape each into a flat, even patty.
04 - Tear 4 large sheets of heavy-duty aluminum foil, approximately 12 inches per side. Brush the center of each sheet with olive oil to prevent sticking.
05 - Arrange sliced potatoes in the center of each oiled foil sheet. Top with layers of sliced onion, red bell pepper, and mushrooms. Season the vegetables lightly with salt and pepper.
06 - Place one seasoned beef patty on top of the layered vegetables in each foil packet. Drizzle each patty with ½ tablespoon of ketchup and a small squeeze of yellow mustard.
07 - Fold the foil over the contents and crimp the edges tightly to form fully sealed packets, ensuring no gaps that could allow juices or steam to escape.
08 - Place the sealed packets on the campfire grate, grill grates, or oven rack. Cook for 20 to 25 minutes, flipping once halfway through, until the beef is cooked through and the vegetables are tender.
09 - Carefully open each packet, watching for hot steam. Place a slice of cheddar cheese on each patty, reseal the packets, and cook for 2 more minutes until the cheese is melted.
10 - Serve directly from the foil packets or transfer to plates. Garnish with sliced pickles, chopped lettuce, tomato slices, and additional condiments as desired.