In a large skillet over medium-high heat, add the ground beef and cook for approximately 7–9 minutes, stirring occasionally until browned. Drain excess fat.

Once the beef is browned, reduce heat to medium and season with salt, black pepper, garlic powder, and onion powder, stirring to combine. Cook for an additional minute.

While the beef cooks, butter one side of each slice of thick-cut bread generously with softened butter.

On a non-buttered side of the bread, layer shredded cheddar cheese, seasoned beef, and shredded mozzarella cheese. Top with another slice of bread, buttered side out.

Carefully place the assembled sandwich into your preheated skillet and grill each side for about 3–4 minutes until golden brown and cheese is melted.

Remove the sandwich from the skillet and let it rest for a minute before slicing in half. Garnish with freshly chopped parsley if desired.