Assemble the sandwiches by layering a slice of the cinnamon raisin bread, grated cheddar, two slices of apple, two slices of crisped bacon, a few good cracks of black pepper, a bit more of the shredded cheese, and another slice of cinnamon raisin bread.
Do this for all four sandwiches, spreading the cheese out equally among them.
In a large heavy bottomed skillet, melt half of the butter over medium heat until foaming. Add the sandwiches to the griddle.
Allow the sandwiches to cook for 1-2 minutes on each side. Before flipping, add the remaining butter to ensure the second side cooks evenly.
Once the bread is lightly crisped on both sides, remove the sandwiches from the griddle. Place sandwiches onto a sheet pan with a metal rack. Bake in preheated oven for just a few minutes, checking often until the cheese is really melted and gooey.