01 - Preheat your campfire grate, outdoor grill, or oven to medium-high heat (approximately 400°F). Allow the heat source to stabilize before cooking.
02 - In a mixing bowl, combine the ground beef with garlic powder, onion powder, smoked paprika, a generous pinch of kosher salt, and freshly ground black pepper. Mix gently just until the seasonings are evenly distributed—avoid overworking the meat.
03 - Divide the seasoned beef mixture into 4 equal portions and shape each into a flat, even patty roughly 1/2 inch thick.
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 thinly sliced potatoes in the center of each oiled foil sheet. Layer sliced onion, red bell pepper, and mushrooms over the potatoes. Season the vegetables lightly with salt and pepper.
06 - Place one seasoned beef patty on top of the vegetables in each packet. Drizzle 1/2 tablespoon of ketchup and a small amount of yellow mustard over each patty.
07 - Fold the foil up and over the filling, crimping the edges tightly to form fully sealed packets. Ensure there are no gaps or openings to prevent juices from leaking during cooking.
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 fork-tender.
09 - Carefully open each foil packet, watching for hot steam. Place a slice of cheddar cheese on top of each patty, then reseal the packets and cook for an additional 2 minutes to allow the cheese to melt.
10 - Open the packets and serve directly from the foil or transfer to plates. Garnish with sliced dill pickles, chopped lettuce, fresh tomato slices, and extra ketchup or mustard as desired.