01 -
Place bacon in a large skillet and cook over medium heat, turning occasionally, until crisp, 8-10 minutes. Transfer to paper towels and wipe out the skillet.
02 -
Spread a thin layer of mayonnaise on one side of each bread slice. Spread Dijon mustard on the plain side of 4 slices.
03 -
Set the Dijon slices mayo-side down. Divide cheddar, Monterey Jack, provolone, bacon, and black pepper over them, then top with the remaining bread, mayo-side up.
04 -
Melt 1 tablespoon butter in the skillet over medium-low heat. Add 2 sandwiches and cook for 3-4 minutes, pressing gently, until the bottoms are deep golden.
05 -
Turn the sandwiches carefully and cook for 3-4 minutes more, until the second side is golden and the cheese is fully melted. Repeat with remaining butter and sandwiches.
06 -
Transfer to a cutting board and rest for 1 minute. Slice diagonally and serve hot while the cheese is still stretchy.