01 -
Preheat the oven to 375 degrees F.
02 -
Slice the loaf of bread in half, lengthwise, and scoop out some of the surface to leave a 1-inch border intact. Spread mayonnaise evenly over both halves and place the bread on a baking sheet.
03 -
In a large nonstick skillet, warm the olive oil over medium-high heat. Add the diced onion, bell pepper, and mushrooms, and sauté until they are tender, about 2 minutes.
04 -
Add the ground beef to the skillet, cooking it as you break it into small crumbles. Continue until no pink remains, about 3 minutes. Drain off any excess fat.
05 -
Stir in the Worcestershire sauce, salt, and black pepper. In a small bowl, whisk together cornstarch and beef broth, then add to the beef mixture. Gently simmer for 2 to 3 minutes, stirring occasionally, until the mixture thickens slightly.
06 -
Divide the filling evenly between the two bread halves and spread it out.
07 -
Sprinkle shredded cheese over the top.
08 -
Bake for about 15 minutes or until the cheese is melted and golden-brown. Alternatively, broil briefly for additional browning if desired.
09 -
Cut into 2-inch portions for appetizers or larger portions for lunch or dinner. Sprinkle with red pepper flakes for added heat and color, if desired. Enjoy!.