For the garlic butter bread:
- 2 baguettes, halved and split, or 4 crusty sub rolls (12 inches each), split
- 6 tablespoons butter
- 4 large cloves garlic, finely chopped
- 2 tablespoons flat leaf parsley, finely chopped
For the French onion steak filling:
- 1 tablespoon extra virgin olive oil (EVOO)
- 2 tablespoons butter
- 2 large or 3 medium onions, very thinly sliced
- Salt and pepper
- 1/2 teaspoon ground thyme
- 1 large fresh bay leaf
- 1/4 cup dry sherry or 1/2 cup dry white wine
- 2 cans beef consommé or 3 cups beef stock
- 4 flat-iron steaks or 1 1/2-2 pounds flank steak, at room temperature
- 3 cups shredded Gruyère cheese
Toast the bread in a 375°F oven to golden. Melt the butter in a small pan over medium heat until it foams. Stir in the garlic, 1-2 minutes, then remove from the heat and stir in the parsley. Brush the toasted bread liberally with the garlic butter and reserve.
To make the steak filling, heat the EVOO in a large skillet over medium heat, then add the butter. When it foams, add the onions and season with salt, pepper, thyme and bay. Cook until caramel in color, 30 minutes. Add the consommé to the onions.
Set the rack in the middle of the oven and switch on the broiler.
Heat a griddle or cast iron skillet over medium-high heat; drizzle with oil. Season the steaks liberally with kosher salt and pepper. Cook for 10 minutes, turning once. Let stand for 5 minutes, then thinly slice against the grain and drop into the onion soup.
Pile the steak and onions onto the toasted bread bottoms arranged on a baking sheet. Top with lots of cheese and melt under the broiler. Set the tops in place and serve.