Add the salt, pepper, paprika and 1 tablespoon of worcestershire sauce to the meat and mix to combine. Let marinade while coming to room temperature or up to 4 hours in the fridge. (If marinating in the fridge, take out 20 minutes before cooking to let come to room temp.)
Turn the broiler on high and line a baking sheet with aluminum foil and the brioche buns, opened. Set aside.
Add a touch of oil to a cast iron skillet over medium-high heat. Add the peppers and onions and a pinch of salt, cooking for 5-8 minutes or until softened and charred. Remove to a plate and set aside.
Add a bit more oil and the meat to the same skillet, breaking up the meat with your spatula. Add 2 more tablespoons of Worcestershire sauce and cook until done, which should only take about 4-5 minutes with how thin shaved beef is.
When the beef is almost done, add the brioche buns to the oven and let toast a few minutes. Make sure to watch these as they can burn fast! After a few minutes, remove, add the provolone and return to the oven to melt (also will only take a few minutes).
When done, pile on the shaved steak and then the peppers and onions.