Aaa Flat Iron Steak Sandwich Recipe

Marinate the steak

Pat the flat iron steak dry with paper towels. In a shallow dish, whisk together 2 tbs olive oil, soy sauce, Worcestershire sauce, minced garlic, black pepper and 1 tsp kosher salt. Add the steak and turn to coat. Cover and refrigerate for 30–60 minutes (up to 4 hours). Bring to room temperature for 20–30 minutes before cooking.

Cook the steak

Heat a cast-iron skillet or heavy griddle over high heat until very hot. Add a light swipe of oil. Remove steak from marinade, blot excess marinade off (reserve juices). Sear steak 3–4 minutes per side for medium-rare (internal temp 125–130°F / 52–54°C), or longer for desired doneness. If the steak is thick, finish in a 400°F (200°C) oven for a few minutes. Transfer steak to a cutting board and rest for 8–10 minutes before slicing thinly against the grain.

Make the pesto while the steak rests. In a food processor combine basil, parsley, toasted pine nuts, Parmesan, 1 garlic clove, lemon juice, salt and pepper. Pulse to a coarse paste. With the processor running, stream in 1/2 cup extra-virgin olive oil until emulsified and spreadable. Taste and adjust salt, pepper or lemon. Transfer to a small bowl and set aside.

Quick-pickle the onions

Place thinly sliced onion in a bowl. In a measuring cup combine 3 tbs apple cider vinegar, 3 tbs water, 1 tsp sugar and 1/2 tsp kosher salt; stir to dissolve. Pour the liquid over the onions, toss, and let sit at room temperature for 15–20 minutes while you prepare the frying station. Drain and reserve the pickling liquid.

Prepare dredge

In a shallow bowl whisk together 1/2 cup flour, 1 tbs cornstarch, 1/2 tsp smoked paprika and 1/4 tsp black pepper.

Fry the onions

Heat 1 cup neutral oil in a medium skillet over medium-high heat to 350°F (175°C) if using a thermometer. Dredge small handfuls of the drained pickled onions in the flour mixture, shaking off excess, and carefully add to the hot oil in batches so they don't stick. Fry until golden brown and crisp, about 2–3 minutes per batch. Use a slotted spoon to transfer to a paper-towel lined tray to drain. Immediately sprinkle a pinch of salt while hot. Return reserved pickling liquid to a small bowl and toss a few fried onions in it briefly (1–2 seconds) to lightly marinate, then return to the tray to crisp. This yields marinated crispy onions with a bright tang.

In a small bowl combine 4 tbs softened unsalted butter with lime zest, lime juice, chili flakes, ground cumin and 1/4 tsp salt. Mash together with a fork until fully combined and smooth. Taste and adjust lime or chili. Keep at room temperature if using immediately or refrigerate and bring back to room temp before assembling.

Toast rolls

Slice rolls and brush cut sides with 1 tsp olive oil. Toast cut sides in a skillet over medium heat until golden, about 2 minutes.

Assemble sandwiches

Spread about 1–1.5 tbs herb pesto on the bottom half of each toasted roll. Layer 4–5 oz sliced flat iron steak per sandwich (slice thin against the grain). Spread 1 tbs chili lime butter on the top half of each roll so it melts onto the steak. Pile a small handful (about 2 tbs) of marinated crispy onions over the steak, add optional tomato slices and a small handful of mixed greens if using. Close sandwiches and press lightly. Serve immediately.

Leftovers & notes: Any leftover pesto keeps refrigerated for 3–4 days. Reheat steak gently or serve at room temperature. If you prefer less heat, reduce chili flakes in the butter.