Gather all ingredients.
Preheat the oven to 450 degrees F (230 degrees C). Grease a 9x13-inch baking dish.
Spread 6 slices of bread with 2 tablespoons butter on one side.
Lay buttered slices of bread, butter side down, on an extra large baking sheet.
Spread bread slices evenly with cream cheese.
Top each bread slice with 2 slices of Cheddar cheese
Top cheese with remaining bread slices.
Spread tops of bread slices with 2 tablespoons butter.
Bake sandwiches for 12 to 14 minutes, flipping once, until cheese is melted. Let sandwiches cool at least 15 minutes. Reduce oven temperature to 350 degrees F (175 degrees C).
Meanwhile, prepare soup mixture. Whisk together tomato soup, tomato juice, eggs, Italian seasoning, and garlic powder in a bowl. Stir in chopped tomato.
Cut toasted sandwiches into 1-inch cubes.
Pour soup mixture into prepared dish.
Place cubes evenly over soup mixture in dish; pressing slightly to submerge in soup mixture.
Sprinkle with shredded Italian blend cheese.
Bake until heated through, golden brown, and cheese is melted, 25 to 30 minutes.