On its most basic level, Carne Asada is a marinated and grilled steak, sliced thin and served on tortillas or used as an ingredient in a wide range of dishes. The basic method is to marinate most any kind of beef in a lime based marinade. Grill it over a hot fire, preferably charcoal, and then slice into thin strips across the grain. But there is a whole lot more to this "Grilled Beef" than that.
Tradition: In Mexico and the American Southwest you will find that Carne Asada has become the modern Spanish equivalent of Barbecue.
I mean that in the party sense of the word. Traditionally a large fire pit is used to prepare this party and a simple, charcoal grill works best. Since the meat is cooked over direct heat you won't be needing a lid. The cut of beef you use doesn't need to be fancy either. Traditionally Carne Asada is made from Skirt Steak. You want a flavorful cut that doesn't need to be tender so if you can't get Skirt Steak go with a Flank Steak, sirloin flap meat, or even trimmed Brisket cut into 1 inch thick "steaks" and then again into thin strips. If you are planning a big party and want to have plenty for everyone plan on up to a pound of meat per person. Of course, if you have lots of side dishes then cut back on the meat.
Marinade: Marinating is not entirely necessary, but it will add flavor and tenderness to your meat and is definitely recommended. A good marinade for Carne Asada will have lots of lime juice, garlic, onion and black pepper.
Of course, other fruit juices work great as well, especially papaya which is a powerful natural tenderizer. You can add hot peppers to the marinade if you want but be careful you don't over power the meat and make it too hot to handle. Don't add salt to your marinade.
Seasoning: Ideally the meat should be cooked over a charcoal fire.
Traditionally mesquite is used, or course. Wood chips in a smoker box will help, but nothing beats the authentic flavor of a real fire. When you get ready to grill you will want to have salt on hand. Use a good coarse salt and add a little cumin, powdered garlic, chili powder and whatever else you like. Shake it together and keep it on hand.
Grilling: The grill should be very hot before you start cooking. Place the meat on the grill and when the juices start to rise on the surface, sprinkle with the salt. When the salt liquefies on the surface flip the meat over and repeat. This seasons the meat as it cooks. Carne Asada is supposed to be on the salty side, but this doesn't mean that you need to add an excessive amount. This salting is also the reason you don't want to use a marinade with salt and is key to what makes Carne Asada taste so good.
Traditionally Carne Asada is grilled to well done. Most people who didn't grow up eating this dish might find that a little hard to swallow so I usually work towards medium.
Once you have the meat grilled to perfection you will want to take it straight to a carving board. Cut the meat across the grain with a good sharp knife. The pieces should be thin strips. Keep the meat warm in a heavy pot with a lid. You don't need to add heat, but you want to hold in the heat you have.
Serving: Serve with warm tortillas and whatever fixings you prefer. A good Carne Asada taco would be topped with salsa, chopped red onion, guacamole, salt and lime wedges. Now that’s a taco. If you have leftovers, make enchiladas the next day. Oh, and serve with lots of your favorite cold beverage.