When you think of flank steak, you might think of fajitas, stews or other meals in which less expensive cuts of meat are slow-cooked until they lose their fibrous texture. Flank steak is a stringy and tough cut of meat from the lower parts of the cow, but if you slow-cook or marinate your flank steak, you will find that it is surprisingly flavorful. Roasted flank steak is usually rolled or stuffed because the flavor of the steak pairs well with a variety of flavors, such as garlic, roasted pepper or even mozzarella cheese.
Preheat your oven to 350 degrees.
Brush olive oil over both sides of the flank steak, then rub Italian seasoning or steak seasoning on both sides of the roast.
Lay down the slices of prosciutto, then the slices of mozzarella or provolone.
Sprinkle the chopped mushrooms and minced garlic evenly over the steak. Add the strips of roasted red pepper over the mushrooms and garlic if you are using them.
Roll the roast tightly into a loaf shape and tie it at the ends and in the middle with kitchen twine.
Heat a cast-iron skillet on medium-high heat and sear the outside of the roast. This will seal in the juices.
Transfer the roast to a broiler pan or leave it in the cast-iron skillet, if you prefer. Place the pan in the oven and cook the roast for one hour. After one hour, take the temperature of the roast with a meat thermometer. The internal temperature should be 160 degrees. If it is less than 160, place the roast back into the oven and cook it for an additional 5 minutes, then take its temperature again. Repeat until the roast is fully cooked.
Allow the roast to stand for 10 minutes before you slice it. Slicing the roast too soon will allow the juices and the cheese to run out.