In a small bowl, combine softened butter with grated Parmesan cheese and garlic powder. Mix until well blended, creating a creamy spread.

Heat a skillet over low to medium heat. Butter one slice of bread and place it buttered-side down onto the skillet.

Layer a slice of cheese on the bread, followed by turkey cold cuts, and another layer of cheese if desired.

Top with another slice of bread, buttered side facing up, and gently press down with a spatula.

After about 5-6 minutes, flip the sandwich and cook for another 5-6 minutes until golden and cheese is melted.

Whisk together mayonnaise, red grape juice vinegar, remaining Parmesan, garlic powder, Italian seasoning, and cracked pepper in a mixing bowl.

Fold in the shredded iceberg lettuce, sliced red onion, and chopped banana peppers into the dressing.

Cut the sandwich open on a diagonal, spoon the salad mixture inside, close the sandwich, and serve.