Preheat a griddle or skillet over medium-high heat. Spread butter on one side of each slice of bread.
Place four slices of bread, butter side down on the counter. Top each piece of bread with two slices of cheese and two slices of tomato. Season with a little salt and pepper, then two slices of bacon and the last two pieces of cheese. Finish them off with the remaining slices of bread, butter side up.
Grill sandwiches until deeply golden on both sides and the cheese has melted.
Cut sandwiches into triangles or four square pieces to serve.
Tip: By buttering the bread edge to edge you get a more even golden color in the end.