01 - Prepare your campfire, grill, or oven to medium-high heat, approximately 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 the seasonings are evenly distributed, being careful not to overwork the meat.
03 - Divide the seasoned beef mixture into 4 equal portions and shape each into a flat 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 potato slices in the center of each oiled foil sheet. Top with layers of onion, bell pepper, and mushrooms. Season the vegetables lightly with salt and pepper.
06 - Place one seasoned beef patty on top of the vegetable layer in each packet. Drizzle each patty with 1/2 tablespoon ketchup and a small squeeze of yellow mustard.
07 - Fold the foil up and over the contents, crimping the edges tightly to form fully sealed packets. Ensure there are no gaps to prevent juices from leaking during cooking.
08 - Place the sealed packets on a campfire grate, grill grates, 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.
09 - Carefully open each packet, watching for hot steam. Place a slice of cheddar cheese on each patty, then reseal the packets and cook for an additional 2 minutes until the cheese is melted.
10 - Open the finished packets and serve directly from the foil or transfer to plates. Garnish with sliced pickles, chopped lettuce, fresh tomato slices, and additional condiments as desired.