Season the Steak
Combine garlic powder, smoked paprika, salt, pepper, chili flakes, and Worcestershire sauce in a small bowl.
Rub the steak with olive oil and coat it evenly with the seasoning mixture. Let it rest for 10 minutes.
Cook the Vegetables
Heat the remaining olive oil in a large skillet over medium-high heat.
Cook the onions and bell peppers for 7–8 minutes until soft and lightly caramelized. Stir in the garlic during the final minute.
Transfer the vegetables to a plate.
Cook the Steak
Using the same skillet, cook the steak for about 3–4 minutes per side for medium-rare or longer if preferred.
Remove from the pan and let it rest for 5 minutes.
Slice the Steak
Slice the steak thinly against the grain for maximum tenderness.
Assemble the Sandwiches
Mix together the mayonnaise and Dijon mustard.
Spread onto each sandwich roll.
Layer with sliced steak, sautéed vegetables, and cheese.
For the ultimate Easy Steak Sandwich Recipe, broil the sandwiches for 1–2 minutes until the cheese melts beautifully.
Top with fresh arugula or lettuce before serving warm.