A new twist on an old standby.
Mix tuna, mayonnaise, balsamic vinegar, onion, and dill pickle together in a bowl.
Spread tuna mixture over 2 slices of bread. Top with American cheese and remaining 2 slices of bread.
Cook in a panini press until bread is crispy and cheese is melted, 3 to 4 minutes.
Per Serving: 381 calories; protein 28.4g; carbohydrates 30.7g; fat 15.8g; cholesterol 48.2mg; sodium 864.8mg.