Lay the 8 slices of French bread flat on a clean wooden prep board.

Slather the interior side of every bread slice with a heavy, generous layer of the thick cranberry sauce. (This provides a sharp, acidic contrast to the rich cheese and meat).

Layer the sliced Muenster cheese directly over the cranberry sauce on the bottom 4 slices of bread.

Fold the roasted turkey evenly over the cheese.

Cap the sandwiches with the remaining 4 slices of bread, placing them cranberry-sauce-side down to securely seal the protein and cheese inside.

In a wide, shallow glass dish or pie plate, vigorously whisk together the 4 large eggs and the 3 cups of whole milk until perfectly unified and frothy.

Carefully submerge each assembled sandwich into the egg wash mixture. Allow each side to soak for exactly 25 seconds. The bread must be highly saturated to create a custard-like interior, but not left so long that the structure turns soggy and collapses.

Place a heavy cast-iron skillet over medium heat. Melt 2 to 3 tablespoons of the unsalted butter until foaming and golden.

Carefully transfer the soaked sandwiches into the hot skillet (working in batches to avoid overcrowding).

Fry aggressively until the bottom side establishes a deeply golden-brown, caramelized crust, about 3 minutes.

Carefully flip the sandwiches with a wide spatula. Cook until the second side is equally golden and the interior cheese is completely molten and oozing from the edges. Add more butter to the skillet as needed for subsequent batches.

Transfer the hot, crispy Monte Cristos to a cutting board. Slice in half on a steep bias to reveal the vibrant layers.

Aggressively dust the tops with a heavy snow of confectioners' sugar using a fine-mesh shaker. Serve immediately while piping hot.