How to Make It
Heat a large griddle over medium-high (about 350°F). Spread both sides of bread evenly with butter. Cook 1 side of bread slices on hot griddle until lightly browned, 3 to 4 minutes. Remove bread from griddle.
Top the toasted side of each of 4 slices with 1 Havarti slice, 1 Cheddar slice, 2 meatloaf slices, 1 tomato slice, another Havarti slice, and another Cheddar slice. Cover each with 1 bread slice, untoasted side out. Place sandwich on griddle, and cook until golden brown and cheese has melted, 3 to 4 minutes per side. Serve immediately.