For the Cheese Sauce:
- Add the butter to a small saucepan preheating over medium-low heat.
- When melted, add the flour and constantly whisk (or it will burn) until the mixture is dark blonde in color, about 4-5 minutes. While whisking, slowly add the milk and raise the heat to medium. Keep whisking so no lumps form in the sauce and cook until the mixture gets rich, creamy, and a little thick, about 5 minutes. You know it's ready when the sauce coats the back of a spoon.
- Take off the heat and add a small handful of white cheddar and whisk until it's incorporated, continue doing this until you have used 1 cup of the grated cheese.
- Put back over low heat and season with the nutmeg, salt, and a couple cracks of fresh pepper. Mix and check for seasoning.
- Take off heat and set aside.
For the Grilled Tomato Slices:
- Preheat a cast iron grill pan over high heat. Quickly sear one side of the tomato until char marks appear, no more than one minute, take off the heat and set aside.
For the Peppered Bacon:
- Preheat oven to 400 degrees. Lay bacon on a sheet tray and grind some pepper on each slice. Bake for 12 minutes until crispy, take out and set aside.
To Build the Sandwich:
- Preheat broiler to low and make sure there is 6 inches between the heating element and the rack. Using a cast iron pan or sheet pan, lay both toasted bread slices down.
- Top each with 2-3 slices of roasted turkey, and one slice of fresh tomato (not grilled), season tomato with a pinch of salt.
- Top each sandwich with a generous amount of cheese sauce. Make sure the sauce is overflowing the edges a little bit.
- Top cheese sauce with shredded orange cheddar and place under the broiler for 5 minutes. Keep your eye on it the entire time so it doesn't burn. You want the cheese sauce to bubble and get brown in spots.
- Take pan out of the oven and top each with a grilled tomato slice, two slices of bacon in a criss-cross pattern, and garnish with chopped parsley.