8 tomato slices, seeds removed, slices drained on paper towels
4 tablespoons mayonnaise
Cook bacon in heavy large skillet over medium heat until brown and crisp, turning occasionally, about 6 minutes. Transfer bacon to paper towels and drain. Wash and dry skillet.
Place 4 bread slices on work surface. Press 1/4 cup grated cheese onto each slice. Top each with 2 tomato slices. Sprinkle with pepper. Place 2 bacon slices atop each, breaking into pieces if necessary to fit. Press 1/4 cup grated cheese over bacon on each. Top sandwiches with remaining bread slices, then spread 1/2 tablespoon mayonnaise over top of each sandwich. Heat 2 heavy large skillets over medium heat. Add 2 sandwiches, mayonnaise side down, to each skillet. Place plate atop both sandwiches to weigh down. Cook sandwiches until bottom is golden brown, about 2 minutes. Spread top of each sandwich with 1/2 tablespoon mayonnaise. Turn sandwiches over, mayonnaise side down. Top with plates and cook until golden brown on bottom, about 2 minutes. Transfer sandwiches to work surface. Cut sandwiches crosswise in half and serve