In a pan on medium high heat add ground beef. Brown until no longer pink, drain the fat. Add onion, green pepper, steak seasoning, salt and pepper to a pan and sauté.
Mix cornstarch and broth in a measuring cup, then add to the beef mixture. Simmer. Slather bottom of the loaf with mayonnaise, then layer with four slices of provolone.
Add the meat and veggie mixture on top, layering four more slices of provolone on top. Add top of bread, also slathered in mayo, to make a sandwich.
Wrap in aluminum foil and bake at 375 degrees Fahrenheit for 30-35 minutes. Slice the sandwich in slices and serve immediately.