Roast beef: Preheat your oven to 450°F (233°C).
Combine kosher salt, black pepper, garlic powder, onion powder, and MSG (if using) in a small bowl to make your roast beef rub.
Rub the olive oil on the beef and coat it with a thin layer all over. Sprinkle the beef with all the rub.
Place the beef on a rack set in a sheet pan and cook at 450 degrees for 20 minutes.
Remove the beef from the oven and reduce the heat to 350°F (175°C). Add the beef back to the oven and cook until the beef temperature hits 120 to 125°F (for rare). This should take somewhere between an hour and an hour and a half, depending on the size and weight of the beef.
Let the beef cool at least an hour in the refrigerator before slicing (preferably two hours). Slice the beef as thinly as possible.
Black pepper bacon: line a sheet pan with aluminum foil. I typically overlap two or three pieces.
Remove the bacon from the package and lay as many slices as you can on the foil-lined baking sheet. You can place your bacon very close together, but try not to overlap the pieces. If you can't get the whole package on there, put the remainder back in the fridge for later.
Sprinkle about half a teaspoon of brown sugar evenly over each slice of bacon. Then grind as much black pepper over all the pieces as you desire. You can use pre-ground black pepper if that's what you have, but this works best with freshly ground black pepper.
Do not preheat your oven. When you have as much bacon as you can fit on your sheet pan, place it in a cold oven and set the oven to 400°F (204°C).
Set a timer for 20 minutes and start checking the bacon. Depending on the type of bacon and thickness, it could take another 5 or more minutes. Because of the brown sugar, the bacon can burn, so keep an eye on it.
I start checking at 20 minutes, and if it's not fully done, I will add a couple of minutes to the timer. Once the bacon is done to your liking, remove the slices to a paper towel-lined plate and store them in the fridge if you're not using them immediately.
Sandwich assembly: add a bit of Parmesan peppercorn ranch (or regular ranch) to the bottom of a six-inch sandwich roll. Top the sauce with some roast beef.
Sprinkle on some shredded cheddar cheese and top with 1 slice of Swiss cheese that you've broken in half so it covers more of the sandwich.
Place the top of the bread roll and the meat and cheese side of the sandwich under the broiler and broil until the cheese is melted and the top of the roll is a bit toasted. If you do not have a broiler, place both sides of the sandwich in a 350°F (175°C) oven for 5 to 7 minutes or until the cheese has melted.
Add 2 slices of bacon on top of the melted cheese, and then spread more Parmesan peppercorn ranch on the top piece of bread. Close the sandwich, serve and enjoy.
Notes:
If you don't want to make the whole Parmesan peppercorn ranch recipe from scratch, here's what I suggest for a one sandwich portion.