01 -
Season chicken with salt and pepper. Cook in oil 6-7 minutes per side until done. Rest before slicing thin.
02 -
Slice avocado, onion, and tomato. Get cheese ready.
03 -
Spread bread with mayo and mustard. Layer chicken, avocado, cheese, onion, and tomato.
04 -
Heat pan with butter. Cook sandwiches 3-4 minutes each side until golden and cheese melts. Press gently with spatula.
05 -
Let cool slightly, cut in half, and serve warm.