Flat-Iron French Dip


Flat Iron Sandwiches with French Onion Au Jus

Flat-Iron French Dip

This recipe is for the serious sandwich lover. The steaks are marinated, then grilled to perfection, sliced and layered onto bread with onions from the au jus, and Swiss cheese.
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Course: Main Dish
Cuisine: American BBQ
Prep Time: 35 minutes
Cook Time: 1 hour 5 minutes
Total Time: 1 hour 40 minutes
Servings: 12 People
Author: Sabrina Baksh


  • 4 pounds flat-iron steaks
  • For marinade:
  • 1/3 cup olive oil
  • 1/4 cup red wine vinegar
  • 1 tablespoon sea salt
  • 2 teaspoons Worcestershire sauce
  • 2-3 cloves garlic, minced
  • For Au Jus:
  • 2 tablespoons beef baste, plus 2 cups water
  • 1 bottle ale
  • 2 medium onions, thinly sliced into rings
  • 2 teaspoons sea salt
  • 2 teaspoons Worcestershire sauce
  • Bread and Toppings:
  • 1/2 cup mayonnaise (and/or mustard)
  • 12 crunchy deli rolls
  • 12 lettuce leaves (optional)
  • 12 slices cheese (swiss or havarti)


  • Place flat-iron steaks in a resealable plastic bag. Combine marinade ingredients and pour over steaks. Make sure steaks are well submerged. Seal bag and place into refrigerator for 4-8 hours.
  • To prepare au jus, combine beef base (I used Better than Bouillon, roast beef base), with 2 cups warm water. Add to a large saucepan. Add ale, sliced onion, and remaining ingredients for jus. Allow mixture to come to a near boil, reduce heat and simmer for 35-45 minutes. If sauce begins to reduce too much, add 1/2 to 1 cup of water until it reaches the right consistency.
  • Preheat grill for medium-high heat (375 degrees F). Remove steaks from bag and place them onto grill. Cook for 8-10 minutes per side, depending on thickness. Once steaks have cooked to desired doneness, remove from grill, tent with foil and allow them to rest for 5-7 minutes before carving. Slice against the grain.
  • To assemble, apply mayonnaise (or mustard) first, then lettuce (optional), two slices of Swiss cheese (or crumbled cheese) per sandwich. Next, place desired amount of simmered onions from au jus, onto bread. Finally add steak slices. Using a ladle, scoop (or strain) au jus , minus onion into a small bowl. Dip sandwich into jus and enjoy.


Photo by robynmac/Depositphotos
Flat-Iron French Dip