Grilled Flat Iron Steak with Garlic Dijon Marinade

By AislePrompt Editorial · Published 2026-06-03 · Updated 2026-06-03

How this recipe was made — this recipe was drafted by AislePrompt's AI-assisted pipeline from technique templates and USDA-sourced nutrition data, and published by AislePrompt Editorial — see how AislePrompt recipes are developed and reviewed.

Tender flat iron steak marinated in a zesty garlic and Dijon mustard blend, grilled to medium-rare perfection with a citrusy finish. This American-inspired beef recipe, ready in about 280 minutes, pairs flat iron steak, olive oil, Dijon mustard for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 350 calories and feeds 4, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Prep: 270 min Cook: 10 min Serves 4 American cuisine 350 cal/serving

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Ingredients

1.5 pounds flat iron steak
3 tablespoons olive oil
2 tablespoons Dijon mustard
4 garlic cloves, minced
2 tablespoons lemon juice
1 teaspoon fresh thyme leaves
1 teaspoon salt
1/2 teaspoon black pepper

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Instructions

Step 1: In a medium bowl, whisk together 3 tablespoons olive oil, 2 tablespoons Dijon mustard, 4 minced garlic cloves, 2 tablespoons lemon juice, 1 teaspoon fresh thyme leaves, 1 teaspoon salt, and 1/2 teaspoon black pepper until well combined and fragrant.
Step 2: Place 1.5 pounds flat iron steak in a large resealable bag and pour the marinade over it, ensuring the steak is fully coated. Seal the bag and refrigerate for 4 hours to tenderize and infuse flavor.
Step 3: Preheat your grill to high heat (about 450°F). Remove the steak from the marinade, letting excess drip off, and discard the marinade.
Step 4: Grill the steak for 4-5 minutes per side for medium-rare, turning once, until a rich brown crust forms and the internal temperature reaches 130°F.
Step 5: Transfer the steak to a cutting board, tent loosely with foil, and let rest for 5 minutes before slicing thinly against the grain to retain juiciness.