- 1 In 10-inch skillet, heat oil and 1 tablespoon butter over medium-high heat. Add onions; cook about 5 minutes, stirring frequently, until onions begin to brown. Reduce heat to medium-low; cook 15 to 20 minutes, stirring frequently, until onions are golden brown. Add balsamic vinegar, sugar and salt; cook and stir 1 to 2 minutes or until onions are dark brown. Transfer onions to bowl; cool 10 minutes.
- 2 Spread 2 teaspoons butter on one side of each slice of bread. On the unbuttered side of 4 bread slices, place 1/2 cup Cheddar cheese. Top each with 2 tablespoons caramelized onions and 1 slice remaining bread, buttered side out. Place Parmesan cheese in shallow dish; carefully press both the buttered sides of each sandwich into Parmesan cheese to make cheese stick to bread.
- 3 Heat 12-inch nonstick skillet over medium heat. Add sandwiches; cook uncovered 4 to 5 minutes or until bottoms are golden brown. Carefully turn; cook 2 to 3 minutes longer or until bottoms are golden brown and Cheddar cheese is melted.
- Make sure to splurge for the high-quality Parmesan cheese, as lower quality cheese won’t form as nice a crust on the outside of the sandwich. You can typically find the good stuff in the specialty cheese section of your grocery store.
- There’s a good reason to use yellow onions when making this dish. Sweet onions, like the Vidalia and Sweet Texas variety are great raw, but they don’t have as rich a flavor as yellow do when cooked.
% Daily Value*:
*Percent Daily Values are based on a 2,000 calorie diet.