Patty Melt Recipe with Super Special Prime Seasoning

Ingredients

• 2 tablespoons butter
• 2 large onions, thinly sliced
• 1 tablespoon light brown sugar
• 1 tablespoon Sherry wine or balsamic vinegar
• ¼ teaspoon Kosher salt and freshly ground black pepper
• ¼ small onion, finely chopped
• 1 pound ground beef chuck (20% fat)
• 1 tablespoon ketchup
• 1 tablespoon Super Special Prime seasoning
• 1 tablespoon vegetable oil
• 8 slices marble rye or seeded rye bread
• 4 ounces aged sharp cheddar, thinly sliced
• 4 ounces Swiss cheese (such as Emmenthal), thinly sliced
• 8 teaspoons mayo (preferably Duke’s)