Quick Parmesan Crusted Patty Melt - Ultimate Cheesy Comfort Sandwich

Name: Quick Parmesan Crusted Patty Melt - Ultimate Cheesy Comfort Sandwich
Cuisine: American
Ingredients: 2 Patty Melts; 1 pound ground beef (80/20 blend); 1 tablespoon Worcestershire sauce; 1 teaspoon garlic powder; 1 teaspoon onion powder; ½ teaspoon salt; ¼ teaspoon black pepper; 2 large yellow onions, thinly sliced; 2 tablespoons butter; 1 tablespoon olive oil; ½ teaspoon salt; 1 teaspoon sugar (optional, helps with caramelization); For the sandwich assembly; 8 slices rye bread (or sourdough); ½ cup grated Parmesan cheese; 8 slices Swiss cheese; 4 tablespoons butter, softened; 2 tablespoons mayonnaise; 2 tablespoons Dijon mustard (optional); Mixing bowl; Cheese grater (if using block Parmesan); Knife for slicing onions; Butter knife