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Grilled Flat Iron Steak with Chimichurri & Charred Onions

Yields4 ServingsPrep Time20 minsCook Time20 minsTotal Time40 mins

Tender, juicy flat iron steak is grilled to perfection and served with a vibrant chimichurri sauce—a zesty blend of parsley, garlic, and vinegar. Charred onions add smoky sweetness, making this dish ideal for backyard dinners or a crowd-pleasing weekend meal.

Grilled Flat Iron Steak with Chimichurri & Charred Onions

For the Steak
 2 lbs flat iron steak (or skirt, flank as substitutes)
 2 tbsp olive oil
 Salt and black pepper, to taste
 Optional: 1 tsp smoked paprika or cumin for extra depth
For the Chimichurri Sauce
 1 cup fresh flat-leaf parsley, finely chopped
 2 tbsp fresh oregano, chopped (or 1 tbsp dried)
 3 cloves garlic, minced
 ½ tsp red pepper flakes (adjust to heat preference)
 ½ tsp salt
 ¼ tsp black pepper
 ⅓ cup red wine vinegar
 ½ cup extra virgin olive oil
For the Charred Onion
 2 large red or sweet onions, sliced into ½-inch thick rounds
 1 tbsp olive oil
 Salt and pepper
 Optional: balsamic glaze or vinegar for drizzle
Marinate the Steak (Optional but Recommended)
1

  1. Rub steak with olive oil, salt, pepper, and optional smoked paprika.

  2. Let sit at room temp for 30 minutes, or refrigerate up to 4 hours (bring to room temp before grilling).

Make the Chimichurri
2

  1. In a bowl, combine parsley, oregano, garlic, red pepper flakes, salt, pepper, and vinegar.

  2. Stir in olive oil slowly until incorporated.

  3. Let sit at room temp for at least 15 minutes (can be made a day ahead).

Prep & Char the Onions
3

  1. Brush onion rounds with olive oil and season with salt and pepper.

  2. Grill on medium-high heat (or stovetop grill pan) for 4–5 minutes per side until tender and nicely charred.

  3. Set aside, drizzle with balsamic vinegar if desired.

Grill the Steak
4

  1. Heat grill (or cast iron pan) to medium-high.

  2. Grill steak for 4–5 minutes per side for medium-rare, depending on thickness (internal temp 130–135°F / 54–57°C).

  3. Transfer to a cutting board, cover loosely with foil, and rest for 5–10 minutes.

Slice & Assemble
5

  1. Slice steak against the grain into thin strips.

  2. Serve topped with generous spoonfuls of chimichurri and a side of charred onions.

Tips for Success
6

  • Flat iron steak is naturally tender and ideal for grilling—no need to over-marinate.

  • Let the chimichurri rest so the flavors meld. Leftovers make a great marinade or salad dressing!

  • Char onions until slightly blackened for max flavor and texture contrast.

Variations
7

  • Swap steak for grilled portobello mushrooms or tofu for a vegetarian twist

  • Add grilled peppers or zucchini to the plate for color and balance

  • Stir a spoon of chimichurri into mayo or yogurt for a creamy side sauce

Suggested Pairings
8

  • Serve with: Roasted potatoes, grilled corn, or a tomato-cucumber salad

  • Drink: Malbec, Syrah, or smoky mezcal cocktail

  • Occasion: BBQ dinner, summer party, date night grill

Nutrition Facts

4 servings

Serving size