A grown-up gourmet grilled cheese! For meat-eaters, add crispy applewood bacon! My husband loves it! You can also use American cheese in place of sharp Cheddar cheese if desired. Enjoy!
Heat a cast-iron skillet or non-stick pan over high heat until skillet is warm; reduce heat to medium.
Arrange 2 bread slices in the hot skillet. Add 1 teaspoon butter under each slice in the skillet; flip bread so butter-side is face-up. Spread about 1 teaspoon mustard onto each bread slice; top with 1 slice Cheddar cheese, 1 slice Swiss cheese, tomato slices, and avocado slices. Top each avocado layer with 1 slice Cheddar cheese, 1 slice Swiss cheese, and 1 slice bread. Spread butter onto top piece of bread; flip sandwich and cook until cheeses are slightly melted, 2 to 3 minutes.
Transfer sandwiches to a microwave-safe plate and heat in microwave until cheeses are fully melted, no longer than 30 seconds.
Per Serving: 860 calories; protein 37.6g; carbohydrates 47.2g; fat 59.7g; cholesterol 133.2mg; sodium 1076.7mg.