When you are craving a juicy steak, this Seared Flank Steak with Herb Butter is the perfect option. We start by searing flavorful, marinated steak, then top it with a delicious herb butter for a company-worthy dinner that is easy enough for a busy weeknight. Make it on your Blackstone Griddle or in a cast iron pan.
Seared flank steak with herb butter starts with an overnight marinade that does most of the work for you. A quick, hot sear on the Blackstone or skillet builds a deeply caramelized crust, and compound butter melted over the top while it rests takes it over the edge.
This is the kind of steak that looks impressive without being complicated, and once you know the grain-slicing trick, the texture is unbeatable every time.
Let's Talk Ingredients
Fresh herbs make a big difference. I used parsley and basil, but rosemary or thyme are great too.
For cooking, use any heat-safe oil. I use avocado oil.
For the marinade, use tamari if you’re gluten-free, or coconut aminos if you’re keto.
Tips & Tricks
- Use an instant-read meat thermometer to ensure that the flank steak is cooked to your liking.
- If you are cooking flank steak on the Blackstone griddle, I recommend using an infrared thermometer to ensure that the griddle is at the proper temperature.
- Compound butter make-ahead: "Roll the herb butter into a log, wrap tightly in plastic, and slice into rounds. Freeze for up to 90 days and pull one out anytime you need a fast, impressive finish on steak, chicken, or roasted veggies.
- Pull at 125°F for medium-rare. The flank carries over to 130°F as it rests on a wire rack. If you wait until the thermometer reads 130°F to pull, you’ll overshoot.
Serving Suggestions
Flank steak pairs well with most lunch and dinner side dishes. Some of my favorites include caprese pasta salad, Mediterranean quinoa salad, Instant Pot jasmine rice, Dauphinoise potatoes, and cheesy scalloped potatoes.
Round the meal out with a green salad with Greek yogurt ranch dressing or homemade Italian dressing.
Tools Needed to Make This Flank Steak Recipe
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- Blackstone Griddle or Cast Iron Pan
- Instant read thermometer
- Food processor
- Infrared Thermometer (for determining the temperature of your griddle or skillet.)
How to Make Seared Flank Steak
Herb Butter
First, make your butter. (If you want ideas on how change the flavor profile of the butter, check out this post on how to make compound butter.)
Flank Steak Marinade
How to Cook Flank Steak on a Blackstone
Pan-Seared Flank Steak
Preheat your cast-iron skillet to high heat.
Add oil and cook the steak in a skillet for 5 minutes per side until an instant-read thermometer reaches 125° F.
Slicing Against the Grain
Always slice flank steak against the grain. You can see the muscle fibers running lengthwise; cut perpendicular to them for the most tender bite. This step makes or breaks the texture. Serve sliced flank steak with herb butter on top.
Want a different method? Try my reverse-sear flank steak, or sous vide flank steak.
Seared Flank Steak with Herb Butter - Blackstone Griddle or Cast Iron
Ingredients
Butter
- ¼ cup unsalted butter at room temperature
- 3 tablespoons chopped fresh parsley
- 3 tablespoons chopped fresh basil
- 1 teaspoon lemon juice
- ½ teaspoon sea salt
- ¼ teaspoon fresh ground black pepper
Steak
- 1 ½ - 2 ½ pounds flank steak
- ¼ cup avocado oil
- ¼ cup soy sauce or gluten-free tamari
- 1 teaspoon garlic powder
- 1 teaspoon oregano
- 1 ½ teaspoons sea salt
- Oil for cooking
Instructions
Butter
- Combine the butter, parsley, basil, lemon juice, salt, and pepper in a food processor.
- Pulse until well combined. Transfer to a piece of parchment paper and form into a log.
- Refrigerate until 30 minutes before serving.
Marinade
- Place the steak in a shallow dish.
- Combine the avocado oil, soy sauce, garlic powder, oregano, and salt in a medium bowl.
- Pour over the steak.
- Allow to sit at room temperature for 1 hour or refrigerate up to overnight.
Blackstone Griddle
- Preheat the griddle to 450° F. (Medium-high)
- Cook the steak until lightly charred and an instant-read thermometer reads 125° F (for medium-rare), about 9 to 10 minutes, flipping halfway through.
- Transfer to a cutting board and top with half of the herb butter. Allow to rest for 10 minutes. (The steak will continue to rise in temperature to about 130° F.)
- Slice the steak against the grain and top with more herb butter if desired.
Skillet
- Preheat the skillet to high heat.
- Add additional oil to the skillet if desired.
- Cook for 5 minutes per side until an instant-read thermometer reads 125° F. (If the steak starts to cook too quickly, turn the heat down to medium.)
- Transfer to a cutting board and top with the herb butter. Allow to rest for 10 minutes.
- Slice the steak against the grain and top with additional herb butter if desired.
Phoebe says
Ohmy!! This was absolutely amazing! Thank you for including instructions on the Blackstone. We're still trying to figure ours out.
Raquel says
This was a lovely steak - juicy and delicious! Will make again soon,
SP says
I coated the steak with salt, pepper, and a light coating of sugar. OUTSTANDING!