Grilled Steak Sandwiches

For the steak

1. Season the sirloin with the garlic powder, salt, and black pepper to taste.
2. Preheat a grill to high. Lightly rub the grates with oil and add the steaks. Grill for about 3 minutes, turn the steaks over, and grill another 3 minutes for medium.
3. Transfer the steak to a cutting board to rest for 5 minutes.

For the sandwiches

1. Split open each piece of bread, then spread each with 1/2 tsp mustard and 1 tbsp mayo. Divide the lettuce and tomatoes among the sandwiches.
2. Thinly slice the steak and divide it amount the sandwiches and serve.