Flank steak used to be a cut I avoided because I thought it was too tough, but I eventually learned that the “chewiness” usually comes from overcooking it or slicing it the wrong way. This recipe has become my standard answer for weeknights when I want something that feels a bit elegant but takes less than thirty minutes. It’s all done in one skillet—you sear the meat hard and fast, and then use the flavorful brown bits stuck to the bottom of the pan to make the sauce.
Fair warning: when you sear a steak this quickly on the stove, your kitchen might get a little smoky. I always turn my exhaust fan to high before the meat hits the pan. The sauce is really what brings this together; the vinegar from the capers and the sharp Dijon cut right through the richness of the beef. It’s a bistro-style meal that is surprisingly forgiving to cook at home.
Ingredients
The Steak
- 1 1/2 pounds flank steak
- 1/2 teaspoon kosher salt
- 1/2 teaspoon freshly ground black pepper
- 1 tablespoon butter
- 1 tablespoon extra virgin olive oil
The Pan Sauce
- 3 tablespoons butter
- 1 tablespoon minced shallot
- 3 tablespoons dry vermouth (or dry white wine)
- 1 tablespoon Dijon mustard
- 1/2 teaspoon Worcestershire sauce
- 2 tablespoons capers, drained
- 1 1/2 tablespoons chopped fresh tarragon
Instructions
- Season the meat: Take the flank steak out of the fridge about 15 minutes before cooking if you can. Pat it dry with paper towels—dry meat sears better than damp meat. Season both sides generously with salt and pepper.
- Sear: Heat a heavy-bottomed skillet (I use cast iron) over medium-high heat. Add 1 tablespoon of butter and the olive oil. Once the butter foams, lay the steak in the pan. Cook for about 3 minutes per side. You are looking for a dark brown crust. For medium-rare, pull it when it hits 125°F.
- Rest: Move the steak to a cutting board and cover it loosely with a piece of foil. Let it rest. This is crucial; if you cut it now, the juices will run out and the meat will be dry.
- Make the sauce: Turn the heat down to low. Add the remaining 3 tablespoons of butter to the dirty pan along with the shallots. Cook for about 30 seconds just to soften them.
- Deglaze and finish: Pour in the vermouth and scrape the bottom of the pan with a wooden spoon to release the stuck-on bits. Whisk in the mustard, Worcestershire, capers, and tarragon. Let it bubble for 2 to 3 minutes until it looks glossy and slightly thick.
- Serve: Slice the steak against the grain into thin strips. Arrange on a plate and spoon the warm sauce over the top.
Why You’ll Love This Recipe
- Speed: Because flank steak is thin, it cooks in about 6 minutes total.
- One Pan: Making the sauce in the same skillet minimizes cleanup and captures all the beef flavor.
- Flavor Balance: The sauce is salty, briny, and creamy all at once, which makes the lean beef taste much richer.
Chef’s Tips for Perfection
- Finding the Grain: Look at the raw meat; you will see lines running across it. That is the grain. When you slice, position your knife perpendicular to those lines. This shortens the muscle fibers and makes the meat tender.
- Vermouth Substitute: If you don’t keep vermouth in the house, any dry white wine (like Sauvignon Blanc) works perfectly. In a pinch, a splash of chicken broth with a squeeze of lemon juice does the job too.
- Don’t Overcook: Flank steak is very lean. If you cook it past medium, it gets tough very quickly. It’s better to undercook it slightly, as it will continue to cook a bit while it rests under the foil.
Storage and Reheating
Store leftovers in an airtight container in the fridge for up to 4 days. Reheating steak without cooking it further is tricky. I usually prefer to slice the cold leftovers very thin and eat them on top of a salad or in a sandwich rather than trying to microwave them.
Nutritional Notes
Flank steak is a lean protein source, but the butter in the sauce adds fat content. The recipe is naturally low in carbohydrates, making it suitable for various low-carb diet plans.
25-Minute Pan-Seared Flank Steak with Mustard Sauce
