French Onion Sliced Steak Croissant Sandwich
- 2 garlic cloves, finely chopped
- 2 tablespoons grill seasoning, such as McCormick's Montreal Steak Seasoning
- 1 teaspoon hot sauce, such as Tabasco
- 2 tablespoons Worcestershire sauce
- 2 tablespoons red wine vinegar
- 5 tablespoons extra-virgin olive oil (EV00)
- 2 pounds flank steak
- 2 large yellow onions, thinly sliced
- 1 tablespoon fresh thyme leaves, chopped (from 4 sprigs)
- Salt and freshly ground black pepper
- 1 cup chicken stock or broth
- 4 large croissants
- 4 slices Gruyere or Emmentaler cheese
Preparation time 10mins
Cooking time 20mins
Heat a grill pan or outdoor grill to high heat.
Preheat the broiler.
In a small bowl, mix the garlic, grill seasoning, hot sauce, Worcestershire sauce, and vinegar. Whisk in about 3 tablespoons of the EVOO. Place the flank steak in a shallow dish and pour the marinade over. Toss to coat thoroughly and marinate for 5 to 10 minutes.
While the steak is marinating, heat a large skillet over medium-high heat with the remaining 2 tablespoons of EVOO (twice around the pan). Add the onions, thyme, salt, and pepper, and cook, stirring frequently, for 7 to 8 minutes, until the onions are deep golden brown. Add the chicken stock and continue to cook for 2 to 3 more minutes, until the chicken stock has almost completely cooked away but the onions are still a little wet with the stock. Remove from the heat and reserve.
Remove the flank steak from the marinade and pat dry.
Grill the flank steak for 6 to 7 minutes on each side. Remove the steak from the grill to a cutting board to rest for about 5 minutes, covered loosely with foil. Thinly slice the flank steak on an angle, against the grain.
Split the croissants in half and arrange on a cookie sheet, cut sides up. Pile some of the onions on the bottoms of each croissant. Arrange a pile of the sliced steak on top of the onions and then follow that with some more onions. Place slices of Gruyère or Emmentaler cheese on top and transfer both the croissant bottoms and tops to the broiler. Melt the cheese and toast the cut sides of the tops, 1 to 2 minutes. Place the croissant tops on the melted cheese. Serve immediately.