For the Sauce:
2 tablespoons butter
2 large onions, quartered and very thinly sliced
1/4 teaspoon dried thyme
1 large bay leaf
Salt and finely ground black pepper
1/2 cup dry white wine
1/2 cup veal stock or beef consomme
3 tablespoons crème fraîche or sour cream.
For the Steaks:
2 1-pound hanger steaks each about 1-inch thick
3 tablespoons EVOO – Extra Virgin Olive Oil, divided
About 2 teaspoons herbes de Provence
Kosher salt and black pepper
Olive oil potato chips, cornichons, watercress and grainy Dijon mustard, for serving.
In a large skillet, melt the butter over medium heat. Add the onions, thyme and bay leaf; season with salt and pepper. Cook, partially covered, stirring occasionally, until the onions are extremely soft and a light caramel color, 20-25 minutes. Add the wine and cook 1 minute. Add the stock and bring to a boil. Cook 1 minute, then remove from the heat and stir in the crème fraîche.
Meanwhile, heat a cast-iron skillet over medium-high. Coat the steaks with 2 tablespoons EVOO, then sprinkle with the herbes de Provence; season with salt and pepper. Using a paper towel, rub the skillet with the remaining tablespoon EVOO. Add the steaks and cook, turning once, about 8 minutes for medium-rare. Let rest 5 minutes.
Slice the steaks against the grain, divide among plates and top with the onion sauce. Serve with the chips, cornichons and watercress. Pass the mustard at the table.