In a bowl, combine the ground beef, parsley, garlic, Worcestershire sauce, and steak seasoning.
Mix thoroughly and shape into 3 equal patties.
Heat a nonstick griddle over medium heat.
Cook the patties for 4 to 6 minutes per side, or until they reach the desired doneness. An instant-read thermometer should register at least 160°F (71°C). Remove the burgers from the griddle and set aside.
Warm a second griddle over medium heat.
Butter one side of each slice of bread. Place half of the bread slices onto the griddle, buttered-side down. Layer each with a slice of cheese, a burger patty, and another slice of cheese. Top with the remaining bread slices, buttered-side up.
Grill the sandwiches until the bread is golden brown and the cheese is melted, about 6 to 10 minutes, flipping halfway through.
