Pan-seared flank steak is rosy in the middle and remains tender and juicy without needing to marinate it beforehand. The mustard caper sauce drizzled over top makes this quick and easy recipe a weeknight win!
My Favorite Method for Cooking Flank Steak When I’m Short on Time
This flank steak recipe is one of the very first things I learned to cook from one of my first cookbooks, Easy Basics for Good Cooking from Sunset magazine.
The flank steak cooks on the stove in under 10 minutes before starting the tangy Dijon mustard and briny caper sauce. Over the years, I’ve tweaked the recipe to make it my own, adding a nob of this or a dash of that. The recipe is pretty perfect as is, but you can have fun with it by adding a few extra flourishes.
Here I’ve added tarragon and chopped shallots, adding even more flavor to the lush mustard sauce drizzled over the oh-so-tender sliced steak. We love it so much; it’s definitely a weeknight dinner that I’ll never stop cooking.
Enjoy!
Heidi’s Tips for Recipe Success
- Cook flank steak to medium-rare. Overcooked steak = dry, tough steak, and this lean cut of beef tastes best when it’s still pink inside. Flank steak has a quick cook time (just 5 to 6 minutes total!), so don’t walk away from the stovetop as it sears.
- Always let your steak rest before serving. I transfer mine to a clean cutting board to prevent it from overcooking in the hot pan, then tent it loosely with foil to trap the heat. A brief rest gives the juices within the steak time to redistribute so they stay inside the meat when it’s sliced rather than spilling out onto the cutting board.
- Cut flank steak against the grain. You’re working with a leaner and more fibrous cut of beef, and by slicing it against the grain you’ll be shortening some of those muscle fibers and creating more tender pieces that are easier to chew.
What You’ll Need for the Mustard Sauce and Seasoning
The full recipe, with amounts, can be found in the recipe card below.
- Salt and pepper — Flank steak has a beautifully rich and beefy flavor that I like to enhance with a simple but generous seasoning of salt and pepper. I tend to avoid strongly flavored dry rubs, which would overpower the flavor of the actual steak.
- Butter and olive oil — Butter makes for a richer tasting sauce, while the oil raises the smoke point and prevents anything from burning.
- Shallot — Adds a more nuanced flavor to the sauce (plus it means I don’t have to chop up both onion and garlic for the sauce since it’s got a hybrid flavor reminiscent of both!).
- Vermouth — Instead of the usual white wine, I like to swap in vermouth when making the Dijon mustard steak sauce. It gives the sauce a mildly earthy, herbal flavor and makes the flank steak taste like it came from a nice restaurant.
- Dijon mustard — Has a more complex flavor that plain yellow mustard. Plus, it thickens the sauce without having to add any heavy cream.
- Worcestershire sauce — Just a dash adds umami richness to the tangy sauce.
- Capers — I chuck these pickled flower buds into just about any recipe I can. They’re nice and briny, which offsets the tangy richness of the sauce.
- Tarragon — We love the aromatic anise-like flavor of this fresh herb. It adds that extra something that the sauce needs.
How to Cook Flank Steak on the Stove
- Season liberally. We’re using just salt and pepper so that the beefy flavor of the steak can really shine.
- Cook over medium-high heat. Let your pan get nice and hot so the flank steak sears instead of steams when it’s placed inside. I pull my flank steak out of the pan when it’s browned on both sides but still pink in the middle (you want an internal temperature of 125ºF at this point).
- Make the mustard sauce while the steak rests. Add the sauce ingredients to the pan drippings for maximum flavor and simmer for just 2 to 3 minutes to thicken.
- Slice against the grain, then serve. Thin slices of flank steak topped with the tangy mustard caper sauce and a sprinkling of tarragon makes for one heck of a dinner, any night of the week.
Want to Grill It Instead? Go For It!
Instead of cooking the flank steak on the stove, you can follow the instructions in my grilled flank steak recipe. Skip the marinade but season liberally with salt and pepper, then top with the Dijon mustard sauce before serving.
If you make this recipe, please let me know! Leave a ⭐️⭐️⭐️⭐️⭐️ rating below, leave a comment to tell us what you think, and tag me on Instagram @foodiecrush.
Pan-Seared Flank Steak with Mustard Sauce
Ingredients
Steak
- 1 ½ pound flank steak
- ½ teaspoon kosher salt
- ½ teaspoon freshly ground black pepper
- 1 tablespoon butter
- 1 tablespoon extra virgin olive oil
Dijon Mustard Sauce
- 3 tablespoons butter
- 1 tablespoon minced shallot
- 3 tablespoons dry vermouth or dry white wine
- 1 tablespoon Dijon mustard
- ½ teaspoon Worcestershire sauce
- 2 tablespoons capers, drained
- 1 ½ tablespoons chopped fresh tarragon
Instructions
- Sear the flank steak. Season the 1 ½ pound flank steak with ½ teaspoon kosher salt and ½ teaspoon freshly ground black pepper. Melt 1 tablespoon of the butter with 1 tablespoon olive oil in a heavy-bottomed skillet over medium-high heat. Place the flank steak in the pan and cook, uncovered, until the meat is browned on both sides but still pink in the center, 5-6 minutes total. Transfer the meat to a cutting board and cover with foil to keep warm.
- Make the mustard sauce. In the same pan over low heat, melt the remaining 3 tablespoons of butter with the pan drippings. Add 1 tablepoon minced shallot, stir, and cook for 30 seconds or until fragrant. Whisk in 3 tablespoons vermouth or dry white wine, 1 tablespoon Dijon mustard, ½ teaspoon Worcestershire sauce, 2 tablespoons capers, and 1 ½ tablespoons chopped fresh tarragon. Cook for 2-3 minutes.
- Slice and serve. Slice the flank steak across the grain into thin slices. Spoon the sauce over the meat and sprinkle with more fresh tarragon if desired.
Nutrition
What to Serve With Pan-Seared Flank Steak
More Easy Recipes Using Steak
Storage Tips
Store the steak and mustard sauce separately and refrigerate for up to 4 days. I suggest gently reheating the steak on the stove for best results. You can also use leftovers to make steak sandwiches, salads, and more.
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