- Combine ground beef, soy sauce, chili powder, cumin and onion powder in a mixing bowl. Mix thoroughly to combine. Form into 4 burger patties.
- Preheat a large cast iron skillet or griddle over medium heat and lightly grease with cooking oil. Grill burgers for 3-4 minutes on each side. Set burgers aside and wipe the skillet clean.
- Heat skillet over medium heat and grease with cooking oil. Place 4 tortillas on the skillet and top each with 1 slice of cheese. Place a burger on each tortilla and heat until the cheese is melted for 1-2 minutes. Set aside on a large plate and top with salsa and shredded lettuce.
- Heat remaining 4 tortillas on the skillet topped with remaining cheese. Cook until the cheese is melted. Immediately place over burger topped tortillas. Cut in half and serve hot with salsa and guacamole.