1. Prepare the Chicken Filling: The Heart of the Sandwich

1. Shred the Chicken: If you haven’t already, shred your cooked chicken using two forks. Pull the meat apart into bite-sized pieces.
2. Combine Ingredients: In a medium bowl, combine the shredded chicken, mayonnaise, Dijon mustard, salt, and pepper.
   • Mix Thoroughly: Stir well to ensure the chicken is evenly coated with the mayonnaise and mustard mixture.
   • Taste and Adjust: Taste the mixture and adjust the seasonings as needed. You may want to add more salt, pepper, or Dijon mustard depending on your preference.

2. Assemble the Sandwich: Building Layers of Flavor

1. Lay Out Bread: Place one slice of garlic bread on a clean surface, butter-side down.
2. Add Chicken Mixture: Spread the prepared chicken mixture evenly over the slice of garlic bread.
   • Generous Layer: Don’t be shy with the filling! A generous layer will ensure a satisfying and flavorful sandwich.
3. Top with Cheese: Sprinkle the shredded mozzarella cheese and grated Parmesan cheese evenly over the chicken mixture.
   • Even Distribution: Make sure the cheese is distributed evenly for optimal melting.

3. Grill the Sandwich: Achieving Golden-Brown Perfection and Melted Cheese

1. Top with Second Slice: Carefully place the other slice of garlic bread on top of the cheese, butter-side up.
2. Heat Skillet: Heat a large skillet or griddle over medium heat.
   • No Need for Extra Oil: The butter on the garlic bread should be sufficient for grilling.
3. Grill the Sandwich: Place the assembled sandwich in the heated skillet.
4. Cook Each Side: Grill for about 4-5 minutes per side, or until the bread is golden brown and crispy, and the cheese is completely melted and gooey.
   • Gentle Pressure: You can use a spatula to gently press down on the sandwich while it’s grilling, which helps to melt the cheese and create a more compact sandwich.
   • Monitor Closely: Keep a close eye on the sandwich to prevent burning. Adjust the heat if necessary.

4. Serve and Enjoy: The Moment of Truth

1. Remove from Heat: Once the sandwich is grilled to perfection, carefully remove it from the skillet using a spatula.
2. Let it Rest: Allow the sandwich to rest for a minute or two before cutting into it. This will allow the cheese to set slightly and prevent the filling from spilling out.
3. Cut and Serve: Cut the sandwich in half or into smaller pieces, if desired. Serve immediately while it’s still warm and the cheese is gooey.