To make the carne asada marinade, place in a blender the garlic, jalapeños, lime juice, orange juice, red wine vinegar, Worcestershire sauce, olive oil, cilantro, oregano, salt, allspice, and cayenne. Blend until well combined. Place the flank steak in a food-safe, non-reactive storage container and pour over it the marinade, evenly coating the meat. Let the meat marinate for at least 4 hours but no longer than 24.
To make the potatoes, preheat the oven to 375°F and line a baking sheet with foil. Pierce the potatoes in several spots with a fork, and stir together the olive oil and salt, and then evenly spread over the potatoes. Place the potatoes on the sheet and bake for 50 minutes to 1 hour, or until they’re soft and can easily be pierced with a fork.
About 30 minutes into the potato-baking time, remove the flank steak from the refrigerator and the marinade, blot the surface of the steak with a paper towel to remove any excess liquid, and allow it to come to room temperature, about 30 minutes.
Once the potatoes are done, remove from the oven and then turn on the broiler. To cook the steak, heat on high a large, ovenproof skillet, preferably cast iron. When a dab of water dropped into the skillet sizzles, add the butter and as soon as it melts, add the steak. Cook the steak for 2 minutes and then flip it and cook for 2 more minutes on the other side. Remove the skillet from the stove and then slide it under the broiler, cooking the steak in the oven 1 minute for medium rare, 2-3 minutes for medium.
Take the steak out of the oven and then remover it from the skillet, allowing it to rest on a plate or platter for 10 minutes. To serve, slice the steak into thin, long slices against the grain of the meat, and then chop these into bite-sized pieces.
To assemble the carne asada potatoes, take a potato, slice it lengthwise across the top and open it, fill it with cheese, then top with the carne asada steak, guacamole, sour cream, and pico de gallo, serving with any additional guacamole or pico on the side.
Notes
To cook this on the grill, after it comes to room temperature, cook for a few minutes on each side until it’s your preferred doneness. The potatoes can also be cooked on the grill, though I’d wrap them in foil first.