Ingredients

For the Chimichurri Compound Butter:

  • 1 cup unsalted butter, softened
  • 1/2 cup fresh parsley, finely chopped
  • 1/4 cup fresh cilantro, finely chopped
  • 2 tablespoons fresh oregano, finely chopped
  • 3 cloves garlic, minced
  • 1 tablespoon red wine vinegar
  • 1 teaspoon red pepper flakes (adjust to taste)
  • 1/2 teaspoon kosher salt
  • 1/4 teaspoon black pepper
  • Zest of 1 lemon

For the Steak:

  • 1.5–2 pounds flank steak
  • 2 tablespoons olive oil
  • 1 tablespoon kosher salt
  • 1 teaspoon black pepper
  • 1 teaspoon smoked paprika
  • 1/2 teaspoon garlic powder

Equipment

  • Cast iron skillet or heavy-bottomed pan
  • Meat mallet or heavy skillet for smashing
  • Mixing bowl
  • Parchment paper or plastic wrap
  • Tongs
  • Meat thermometer (optional)

Instructions

Step 1: Prepare the Chimichurri Compound Butter

  1. In a mixing bowl, combine softened butter, parsley, cilantro, oregano, minced garlic, red wine vinegar, red pepper flakes, salt, black pepper, and lemon zest.
  2. Mix thoroughly until all ingredients are evenly incorporated.
  3. Place the mixture on a sheet of parchment paper or plastic wrap. Roll into a log shape, about 1.5 inches in diameter, and twist the ends to seal.
  4. Refrigerate for at least 1 hour to firm up, or until ready to use.

Step 2: Prepare the Flank Steak

  1. Pat the flank steak dry with paper towels to remove excess moisture.
  2. In a small bowl, mix kosher salt, black pepper, smoked paprika, and garlic powder.
  3. Rub the steak with olive oil, then evenly coat both sides with the spice mixture.
  4. Let the steak sit at room temperature for 20–30 minutes to ensure even cooking.

Step 3: Sear the Steak

  1. Heat a cast iron skillet or heavy-bottomed pan over high heat until very hot (smoking slightly).
  2. Add a thin layer of olive oil to the skillet.
  3. Place the flank steak in the skillet and sear undisturbed for 3–4 minutes per side to develop a deep brown crust. (For medium-rare, aim for an internal temperature of 130–135°F / 54–57°C.)
  4. Remove the steak from the skillet and place it on a cutting board.

Step 4: Smash the Steak

  1. Slice the chimichurri compound butter into 1/4-inch thick rounds.
  2. Place 2–3 rounds of the butter on top of the seared steak.
  3. Using a meat mallet or the bottom of a heavy skillet, gently smash the steak to flatten it slightly, allowing the butter to melt into the meat and create a crispy edge. Be careful not to over-smash; aim for a thickness of about 1/2 inch.
  4. Return the steak to the skillet over medium heat for 1–2 minutes per side to crisp up the butter-infused surface and finish cooking to your desired doneness.

Step 5: Rest and Serve

  1. Transfer the steak to a cutting board and let it rest for 5 minutes to redistribute juices.
  2. Slice the steak thinly against the grain for maximum tenderness.
  3. Serve with additional chimichurri compound butter on top or on the side for extra flavor.

Serving Suggestions

  • Pair with roasted potatoes, grilled vegetables, or a fresh green salad.
  • Drizzle with extra chimichurri sauce (made from the same herb mixture, thinned with olive oil) for a vibrant kick.

Notes

  • The chimichurri butter can be made ahead and stored in the refrigerator for up to 1 week or frozen for up to 3 months.
  • Adjust the red pepper flakes in the butter to control the heat level.
  • For a smokier flavor, grill the steak instead of searing in a skillet, then smash with butter on a hot griddle.