Chicken Avocado Melt Sandwich

Season the Chicken: Season the chicken breasts with salt and pepper.
Cook the Chicken: Heat olive oil in a skillet over medium-high heat. Cook the chicken for 6-7 minutes per side until fully cooked. Let it rest for a few minutes, then slice thinly.
Prepare the Ingredients: Slice the avocado, tomato, and red onion. Set aside the cheese and bread.
Assemble the Sandwich: Spread mayonnaise and Dijon mustard on one side of each slice of bread. Layer the sliced chicken, avocado, cheese, red onion, and tomato on two slices of bread. Top with the other slices of bread.
Grill the Sandwich: Heat butter or olive oil in a skillet over medium heat. Grill the sandwich for 3-4 minutes per side until the bread is golden brown and the cheese is melted.
Serve: Once grilled, remove the sandwich from the skillet, slice, and serve hot.
Serving and Storage Tips: