1 1/4 pounds skirt steak (fat trimmed), cut into 4 pieces and patted dry
Coarse salt and ground pepper
2 tablespoons extra-virgin olive oil
<u>Reserved polenta</u>, cut into 8 wedges
4 cups <u>reserved leeks</u>
3 ounces baby arugula (about 3 cups)
1/2 cup loosely packed fresh parsley leaves
Lemon wedges (optional), for serving
Preheat oven to 250 degrees. Heat a large cast-iron or heavy skillet over medium-high. Season steak on both sides with salt and pepper. In two batches, cook steak until browned, 6 minutes per batch, flipping once. Transfer to a rimmed baking sheet, loosely tent with foil, and keep warm in oven. Wipe skillet clean and return to heat. Add 1 tablespoon oil and cook half the polenta wedges until crisp, about 5 minutes, flipping once. Repeat with remaining oil and polenta. Transfer to sheet with steak. Add leeks to skillet, season with salt and pepper, and cook until softened, stirring frequently, 3 minutes.
Toss together arugula and parsley. Thinly slice steak against the grain and serve with salad, polenta wedges topped with leeks, and lemon wedges, if desired.