Prepare the avocado mixture: In a bowl, mash the ripe avocado until smooth but slightly chunky. Add lemon juice, salt, pepper, and garlic powder. Mix well to combine. The lemon juice helps keep the avocado fresh and prevents browning while adding a light, fresh flavor. Set aside.
Prepare the chicken filling: If your chicken is not already seasoned, lightly toss it with a small pinch of salt and pepper. You can use leftover roasted chicken, grilled chicken, or even rotisserie chicken for convenience. Make sure the chicken is cut into thin slices or shredded so it melts nicely inside the sandwich.
Assemble the sandwiches: Lay out the bread slices on a clean surface. Spread a thin layer of mayonnaise on one side of each slice for extra flavor and golden browning. On four slices, add a slice of provolone or Swiss cheese first. Then layer the cooked chicken evenly on top. Spread a generous amount of the mashed avocado mixture over the chicken. Sprinkle shredded mozzarella or cheddar cheese on top to create a gooey melt. Add optional toppings like tomatoes or spinach if desired. Place the remaining bread slices on top to close the sandwiches.
Butter the bread: Lightly spread softened butter on the outside of each sandwich (both top and bottom sides). This step helps create a crispy, golden crust when grilling. Make sure the butter is evenly spread to avoid burning.
Grill the sandwiches: Heat a large skillet or grill pan over medium heat. Place the sandwiches in the pan and cook for about 3–4 minutes per side. Press gently with a spatula to help the cheese melt and the bread toast evenly. Cook until the bread is golden brown and the cheese inside is fully melted. Adjust heat if necessary to prevent burning while ensuring the inside becomes warm and creamy.
Serve: Remove the sandwiches from the pan and let them rest for 1–2 minutes before cutting. Slice in half for easier serving. Serve warm with fries, a fresh salad, or a bowl of soup for a complete meal. Enjoy the creamy avocado, tender chicken, and melted cheese in every bite.