Carne Asada

Method

1. mix8 min
   non-reactive bowl or bag — not aluminium
   orange juice + lime juice + garlic + cilantro + cumin + oregano + olive oil + pepper (+ serrano, + soy sauce, + beer), whisked. Hold the salt back if you plan a long marinade, and use glass or plastic: this much acid reacts with aluminium and picks up a metallic taste
2. marinate180 min
   refrigerated, 2-4 hours, turned once — no longer than 6
   beef in the marinade. Two to four hours is the window. Marinade penetrates only a few millimetres whatever the label claims, so longer buys almost no extra flavour while the citric acid keeps working on what it has reached — past six hours the surface goes opaque and mealy, cooked by acid rather than heat, and it will never take a proper char
3. season15 min
   out of the marinade, wiped nearly dry, salted, 15 minutes at room temperature
   the steak wiped down and + salt applied now. Wipe it dry: a wet surface has to boil off before it can brown, and the herbs clinging to it will burn to bitter specks on a hot grill. Letting it lose the refrigerator chill means less time over the fire to reach the centre
4. grill6 min
   hottest possible fire or a smoking cast iron pan, 2-3 minutes a side, uncrowded
   steak over direct high heat until deeply charred outside and about 52-55°C inside for medium rare. A thin cut gives you a very short window in which the crust forms before the interior overshoots, so the fire has to be genuinely hot — a moderate grill cooks it through grey before any char appears. Leave it alone; each turn restarts the browning
5. rest8 min
   board or warm plate, loosely tented, 5-10 minutes
   before cutting. Skirt and flank are coarse-grained cuts under real tension after high heat, and resting lets the fibres relax and reabsorb liquid that would otherwise be lost on the board
6. slice5 min
   against the grain, sharp knife, thin, on a slight bias
   across the grain into thin strips (+ onion, + lime, in warmed tortillas). This is not presentation — skirt and flank have long, tough muscle fibres, and slicing across shortens them to a few millimetres so the teeth cut them easily. Cut the same steak along the grain and it is genuinely chewy. Find the direction of the lines on the surface and cut perpendicular to them