Heat the olive oil in a large skillet over medium-high heat.
Add the sliced onions and bell peppers. Sauté until soft, about 5–7 minutes.
Push the veggies to one side of the pan and add the beef. Cook until browned, about 3–5 minutes.
Mix the beef and veggies together, seasoning with salt and pepper.
Lay the cheese over the meat and veggie mix and let it melt.
Slice the hoagie rolls and toast them lightly.
Spoon the cheesy beef mixture into the rolls and serve hot.