Place steak into freezer for 30-40 mins.
Combine the garlic and butter thoroughly and spread over the the rolls.
Slice steaks into ⅛” slices and put into a bowl to come up to room temp.
Use a full chimney of charcoal to light BBQ, and separate into direct and indirect zones.
Place a cast iron griddle over direct heat, add a drizzle of oil and add onions and peppers. Cook until softened and edges are slightly charred, then transfer to a bowl and cover with foil to keep warm.
Place the cast iron pan over direct heat again and get as hot as you can.
Add salt and pepper and a drizzle of oil to the steak slices, and mix well.
Add the steak to the cast iron pan and fast cook it, turning it often with tongs.
Once the steak is caramelized and the edges are lightly charred, add the cooked peppers and onion, and mix thoroughly. Remove to indirect heat, add a chunk of smoking wood to charcoal and cover BBQ for 5 mins.
Separate into 2 piles for sandwiches, and add 2 slices of Provolone or Swiss cheese to each pile and allow to melt.
Heat the rolls in the oven at 390°F for 5 mins. Alternatively, cook in BBQ indirect for the same time once lit, and finish face down over coals to crisp.
Spread bottom of toasted roll with horseradish.
Using a spatula, transfer the pile of steak/peppers/cheese to the bottom of the roll.
Add grated truffle cheddar or a drizzle of truffle oil.
Top with a squirt of American mustard, and then the other side of the toasted hoagie roll.
Serve with a crisp American lager.
Enjoy!