grilled steak and onion sandwich... 30 minutes

the goods:

1 teaspoon Dijon mustard

1 tablespoon plus 1/2 teaspoon balsamic vinegar

2 tablespoons plus 1 teaspoon extra-virgin olive oil

1 pound skirt steak

1 red onion, sliced into 1/2-inch-thick rounds

4 sliced crusty bread

spinach leaves

finely grated Parmesan

In a large baking dish, whisk together mustard, 1 tablespoon vinegar, and 2 tablespoons oil. Season with salt and pepper. Add steak and turn to coat; let sit 15 minutes at room temperature.

Heat 1 teaspoon oil in a cast-iron skillet over medium-high. Season onion with salt and pepper and cook until tender, 5 to 7 minutes.

Meanwhile grill steak over medium-high heat until medium-rare, about 5 to 7 minutes, flipping once. Let steak rest 5 minutes before thinly slicing against the grain.

Meanwhile, in a food processor, process onions until finely chopped, then mix with 1/2 teaspoon vinegar. Season to taste with salt and pepper.

Spread onion mixture on bread, top with steak, spinach, Parmesan, and more bread.

Enjoy!