1 Heat the olive oil in a skillet over medium heat. Season the chicken breasts with salt and pepper, then cook for 6-7 minutes on each side until fully cooked. Remove from heat and set aside to cool slightly.
2 While the chicken cools, slice the avocado and set aside.
3 Butter one side of each slice of bread.
4 Slice the cooked chicken breasts and place them on the unbuttered side of two slices of bread. Top with sliced avocado and cheese.
5 Place the other slice of bread on top, buttered side facing out.
6 Grill the sandwiches in the skillet over medium heat for 3-4 minutes per side, until the bread is golden brown and the cheese is melted.
7 Serve hot and enjoy!