How Long to Cook Marinated Skirt Steak (Outside Skirt, Whole 1.5 lb Piece) in the cast iron
Specification: 1.25–1.5 lb outside skirt steak in one piece (about 1/2-inch thick), marinated 2–4 hours in oil, garlic, lime and salt, patted dry before cooking
3-Step Execution Protocol
Heat cast iron skillet over Screaming hot (550°F+ surface) — pan smoking before the steak goes down until lightly smoking. Prepare marinated skirt steak (outside skirt, whole 1.5 lb piece) (1.25–1.5 lb outside skirt steak in one piece (about 1/2-inch thick), marinated 2–4 hours in oil, garlic, lime and salt, patted dry before cooking).
Cook for 3–5 mins (90 seconds per side, no second flip). Flip at the 2-minute mark for even browning.
The exterior is a dark, blistered crust with visibly charred edges where the loose fringes hang off the muscle; the steak has firmed to a springy medium-rare and the marinade sugars have caramelised almost to burnt in patches. Confirm internal temperature reaches 125°F (pull) → 130–135°F medium-rare after 5-min rest. Rest for 5 minutes before serving.
USDA FSIS 145°F whole-cut beef minimum internal temperature with 3-min rest; medium-rare pull of 125°F with 5-min rest documented per Serious Eats skirt steak guide (thin cuts carryover slower than thick ones, ~5–10°F rise) and ThermoWorks technique reference. Grain direction and 1/4-inch cross-cut per J. Kenji López-Alt "The Food Lab" chapter on skirt and hanger steaks.