This recipe is my take on fast food. Skirt steak comes from the flank, or diaphragm, of the cow. It was sold cheaply for years because few people were aware of its tenderness and deep flavor. Now, thanks to the ubiquity of fajitas, which popularized this cut, skirt steak has become pricier, but it has no surface fat or bone, so nothing is wasted. Because it’s so thin, the steak can be on the table in less than 10 minutes. The marinade brings out the assertive beefy flavors.
Pat the steak dry with paper towels and place it in a nonreactive baking pan.Peel and grate the ginger. Juice the lime. In a small bowl, mix the ginger with the lime juice and soy sauce. Smash 2 of the garlic cloves and add them to the marinade. Pour the mixture over the steak, cover, and marinate in the refrigerator for 2 hours.Remove the steak from the marinade and place on a platter. Discard the garlic and ginger and reserve the marinade.Bring the red wine to a boil in a small saucepan over medium-high heat. Chop the shallots and add them to the wine. Boil to reduce the wine to 1/4 cup. Stir in the butter and salt and pepper to taste. Set aside.Meanwhile, heat the broiler. Slice the onion into 1/4-inch-thick rounds and place on a baking sheet. Sprinkle with the reserved marinade and broil the onion until tender and dark brown, about 10 minutes; be careful not to burn it. Transfer to a plate and set aside. Leave the broiler on.Place the steak on the broiler pan and broil, turning once, just until medium-rare, about 4 minutes per side. Transfer to a cutting board and cover loosely to keep warm.Toast the bread on both sides under the broiler.Meanwhile, reheat the sauce over low heat. Split the remaining garlic clove in half and rub the slices of toast with the garlic. Place a slice of toast on each plate. Divide the onion among the toasts. Slice the steak and place on the plates. Top the steak with the red wine sauce and serve.