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.
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Yields4 ServingsPrep Time20 minsCook Time20 minsTotal Time40 mins
For the Steak
2lbsflat iron steak (or skirt, flank as substitutes)
2tbspolive oil
Salt and black pepper, to taste
Optional: 1 tsp smoked paprika or cumin for extra depth
For the Chimichurri Sauce
1cupfresh flat-leaf parsley, finely chopped
2tbspfresh oregano, chopped (or 1 tbsp dried)
3clovesgarlic, minced
½tspred pepper flakes (adjust to heat preference)
½tspsalt
¼tspblack pepper
⅓cupred wine vinegar
½cupextra virgin olive oil
For the Charred Onion
2large red or sweet onions, sliced into ½-inch thick rounds
1tbspolive oil
Salt and pepper
Optional: balsamic glaze or vinegar for drizzle
Marinate the Steak (Optional but Recommended)
1
Rub steak with olive oil, salt, pepper, and optional smoked paprika.
Let sit at room temp for 30 minutes, or refrigerate up to 4 hours (bring to room temp before grilling).
Make the Chimichurri
2
In a bowl, combine parsley, oregano, garlic, red pepper flakes, salt, pepper, and vinegar.
Stir in olive oil slowly until incorporated.
Let sit at room temp for at least 15 minutes (can be made a day ahead).
Prep & Char the Onions
3
Brush onion rounds with olive oil and season with salt and pepper.
Grill on medium-high heat (or stovetop grill pan) for 4–5 minutes per side until tender and nicely charred.
Set aside, drizzle with balsamic vinegar if desired.
Grill the Steak
4
Heat grill (or cast iron pan) to medium-high.
Grill steak for 4–5 minutes per side for medium-rare, depending on thickness (internal temp 130–135°F / 54–57°C).
Transfer to a cutting board, cover loosely with foil, and rest for 5–10 minutes.
Slice & Assemble
5
Slice steak against the grain into thin strips.
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
Ingredients
For the Steak
2lbsflat iron steak (or skirt, flank as substitutes)
2tbspolive oil
Salt and black pepper, to taste
Optional: 1 tsp smoked paprika or cumin for extra depth
For the Chimichurri Sauce
1cupfresh flat-leaf parsley, finely chopped
2tbspfresh oregano, chopped (or 1 tbsp dried)
3clovesgarlic, minced
½tspred pepper flakes (adjust to heat preference)
½tspsalt
¼tspblack pepper
⅓cupred wine vinegar
½cupextra virgin olive oil
For the Charred Onion
2large red or sweet onions, sliced into ½-inch thick rounds
1tbspolive oil
Salt and pepper
Optional: balsamic glaze or vinegar for drizzle
Directions
Marinate the Steak (Optional but Recommended)
1
Rub steak with olive oil, salt, pepper, and optional smoked paprika.
Let sit at room temp for 30 minutes, or refrigerate up to 4 hours (bring to room temp before grilling).
Make the Chimichurri
2
In a bowl, combine parsley, oregano, garlic, red pepper flakes, salt, pepper, and vinegar.
Stir in olive oil slowly until incorporated.
Let sit at room temp for at least 15 minutes (can be made a day ahead).
Prep & Char the Onions
3
Brush onion rounds with olive oil and season with salt and pepper.
Grill on medium-high heat (or stovetop grill pan) for 4–5 minutes per side until tender and nicely charred.
Set aside, drizzle with balsamic vinegar if desired.
Grill the Steak
4
Heat grill (or cast iron pan) to medium-high.
Grill steak for 4–5 minutes per side for medium-rare, depending on thickness (internal temp 130–135°F / 54–57°C).
Transfer to a cutting board, cover loosely with foil, and rest for 5–10 minutes.
Slice & Assemble
5
Slice steak against the grain into thin strips.
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
Notes
Grilled Flat Iron Steak with Chimichurri & Charred Onions
