01 - Prepare your campfire, outdoor grill, or oven to medium-high heat, targeting approximately 400°F.
02 - In a mixing bowl, combine the ground beef with garlic powder, onion powder, smoked paprika, salt, and pepper. Mix gently until just incorporated, being careful not to overwork the meat.
03 - Divide the seasoned beef mixture into 4 equal portions and set aside.
04 - Tear 4 large sheets of heavy-duty aluminum foil, roughly 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. Layer onion slices, bell pepper strips, and mushrooms evenly over the potatoes. Season the vegetables lightly with salt and pepper.
06 - Flatten each beef portion into a patty and place one on top of the vegetables in each packet.
07 - Drizzle approximately 1/2 tablespoon of ketchup and a small squeeze of yellow mustard over each patty.
08 - Fold the foil up and over the filling, crimping the edges tightly to form fully sealed packets. Ensure there are no gaps to prevent juices from leaking during cooking.
09 - Place the sealed packets directly on the 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.
10 - Carefully open each packet, watching for hot steam. Place a slice of cheddar cheese on each patty, then reseal the packets and let them rest for 2 minutes until the cheese melts.
11 - Serve directly from the foil packets or transfer to plates. Garnish with sliced pickles, chopped lettuce, fresh tomato slices, and additional condiments as desired.