Aug 30 2026
RestaurantsFluid Bar & GrillFlat Iron Steak Sandwich Recipe

Flat Iron Steak Sandwich Recipe

Inspired by Fluid Bar & Grill
Time1h
Serves2

Marinated steak, herb pesto, grilled focaccia

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Ingredients

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Marinated Steak

Method

Marinated Steak

  1. 1

    Prepare Marinade

    In a shallow bowl or resealable plastic bag combine 3 tbs olive oil, 2 tbs soy sauce, 1 tbs red wine vinegar, 1 tsp Worcestershire sauce, 3 crushed garlic cloves, 1 tsp smoked paprika, 1 tsp cracked black pepper and 1 tsp kosher salt. Whisk or shake until emulsified.

  2. 2

    Marinate Steak

    Trim any excess fat from the 1 lb flat iron steak. Place the steak in the bowl or bag with the marinade and turn to coat. Refrigerate for at least 30 minutes and up to 4 hours (avoid longer for this cut to prevent overly soft texture). Remove steak from fridge 20 minutes before cooking to come closer to room temperature.

  3. 3

    Sear and Rest

    Preheat a grill or heavy skillet (cast iron) over medium-high heat until very hot. Pat steak dry with paper towels and rub off excess marinade. Lightly oil the grill or pan. Sear the steak 3–4 minutes per side for medium-rare (internal temp 125–130°F / 52–54°C), or longer for desired doneness. Use tongs to flip once. Transfer to a cutting board and tent loosely with foil. Rest 8–10 minutes before slicing thinly against the grain.

Herb Pesto

  1. 4

    Blend Pesto

    In a small food processor combine 1 cup basil leaves, 1/2 cup parsley, 1 garlic clove, 2 tbs pine nuts, 3 tbs grated Parmesan, 1 tsp lemon juice, 1/4 cup olive oil, 1/2 tsp salt and 1/4 tsp black pepper. Pulse until a spreadable paste forms, scraping down sides as needed. If too thick, add olive oil 1 tsp at a time to reach desired consistency. Taste and adjust salt/lemon.

  2. 5

    Hold

    Transfer pesto to a bowl and cover; keep at room temperature if assembling immediately or refrigerate up to 24 hours. Bring back to room temperature before spreading if chilled.

Bread & Assembly

  1. 6

    Prep Bread and Veggies

    Slice the focaccia loaf horizontally to make sandwich halves. Brush cut sides lightly with 2 tbs olive oil. Thinly slice 1 tomato and 1/4 medium red onion. Toss tomato and onion with 1/4 tsp salt and 1/4 tsp pepper. If using cheese, have 4 slices ready.

  2. 7

    Grill Focaccia

    Preheat a grill or skillet to medium heat. Place cut focaccia, cut-side down, on the grill or skillet and toast 1–2 minutes until golden and slightly crisp. Remove and keep warm.

  3. 8

    Assemble Sandwiches

    Spread a generous layer (about 2–3 tbs) of herb pesto onto both cut faces of the toasted focaccia. On the bottom half, layer arugula (about 1 cup), then the thinly sliced rested flat iron steak (arrange to cover surface). If using, place cheese slices on top of hot steak to let them soften. Add tomato and red onion slices. Finish with the top half of focaccia. Press gently and slice into 2–4 portions.

  4. 9

    Serve

    Serve immediately while steak is warm and bread is crisp. Optional: provide extra pesto or a side of pickles or potato chips.

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