-
1
Heat a grill pan or outdoor grill to high heat.
-
2
Preheat the broiler.
-
3
In a small bowl, mix the garlic, grill seasoning, hot sauce, Worcestershire sauce, and vinegar.
-
4
Whisk in about 3 tablespoons of the EVOO.
-
5
Place the flank steak in a shallow dish and pour the marinade over.
-
6
Toss to coat thoroughly and marinate for 5 to 10 minutes.
-
7
While the steak is marinating, heat a large skillet over medium-high heat with the remaining 2 tablespoons of EVOO (twice around the pan).
-
8
Add the onions, thyme, salt, and pepper, and cook, stirring frequently, for 7 to 8 minutes, until the onions are deep golden brown.
-
9
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.
-
10
Remove from the heat and reserve.
-
11
Remove the flank steak from the marinade and pat dry.
-
12
Grill the flank steak for 6 to 7 minutes on each side.
-
13
Remove the steak from the grill to a cutting board to rest for about 5 minutes, covered loosely with foil.
-
14
Thinly slice the flank steak on an angle, against the grain.
-
15
Split the croissants in half and arrange on a cookie sheet, cut sides up.
-
16
Pile some of the onions on the bottoms of each croissant.
-
17
Arrange a pile of the sliced steak on top of the onions and then follow that with some more onions.
-
18
Place slices of Gruyere or Emmentaler cheese on top and transfer both the croissant bottoms and tops to the broiler.
-
19
Melt the cheese and toast the cut sides of the tops, 1 to 2 minutes.
-
20
Place the croissant tops on the melted cheese.
-
21
Serve immediately.
