Chef John'S Ultimate Steak Sandwich - cooking recipe

Ingredients

1 (2 pound) fully-trimmed flat iron steak
salt and pepper
8 ounces brown clamshell mushrooms, grilled, separated
salt and pepper to taste
1 tablespoon sherry vinegar
2 tablespoons extra virgin olive oil
3 tablespoons barbeque sauce
2 tablespoons vegetable oil
1 tablespoon cider vinegar
6 hot dog buns
1/2 cup mayonnaise, or as needed
1 cup arugula leaves, or as needed
1 cup quartered cherry tomatoes

Preparation

Preheat an outdoor grill for medium-high heat, and lightly oil the grate.
Cut steak into 6 thick strips. Season generously with salt and pepper.
Grill mushrooms for 5-6 minutes over medium-high heat until they begin to wilt. Remove the stem end to separate the mushrooms.
Stir mushrooms in a bowl with salt and pepper, sherry vinegar, and extra virgin olive oil. Set aside.
Grill steaks for 3-4 minutes per side over medium-high heat, until medium rare or to desired doneness. An instant-read thermometer inserted into the center should read 140 degrees F (60 degrees C). Let rest for 5 minutes.
Whisk together barbeque sauce, cider vinegar and vegetable oil. Set aside.
Serve grilled steaks on hot dog buns with mayonnaise, arugula, cherry tomatoes, grilled mushrooms, and barbeque sauce mixture.