Creating the Irresistibly Chicken Avocado Melt Sandwich is straightforward if you follow these steps:

1. Prepare the Chicken: In a bowl, combine the shredded chicken, mayonnaise, lime juice, garlic powder, salt, and pepper. Mix well until the chicken is evenly coated.
2. Mash the Avocado: In another bowl, mash the ripe avocado with a fork. Add a pinch of salt and pepper to taste.
3. Assemble the Sandwich: On two slices of bread, spread a generous layer of the chicken mixture. Top with a layer of mashed avocado and a sprinkle of shredded cheese.
4. Top and Butter: Place the remaining slices of bread on top. Spread a thin layer of butter on the outside of each sandwich.
5. Heat the Pan: Preheat a skillet over medium heat. Once hot, place the sandwiches in the skillet.
6. Cook Until Golden: Cook the sandwiches for about 3-4 minutes on each side, or until the bread is golden brown and the cheese has melted.
7. Serve: Remove the sandwiches from the skillet and let them cool for a minute. Cut in half and garnish with fresh cilantro or parsley, if desired.