Top each of 2 of the bread slices with 1 slice of mozzarella cheese.
Spread on half of the mashed avocado. Top with 1 slice of tomato, 2 slices of turkey, 2 slices of bacon, one more slice of mozzarella cheese and the remaining bread slice.
Spread butter onto the top of the top slice of bread.
Heat a large skillet to medium-low heat. Place sandwiches into the skillet butter side down. Spread butter on top of each sandwich.
Cook over medium-low heat turning once for about 6-8 minutes or until the bottom is golden brown.
Turn the sandwiches and cook for 5-6 minutes longer or until golden brown and the cheese has melted.