In this simple steak dish, the marinade is strained and cooked down to become the sauce.
In a shallow dish, whisk lemon juice, Worcestershire, mustard, 1 tablespoon olive oil, sugar, garlic, salt, and pepper.
Pierce steak all over with a fork; toss in marinade. Marinate 30 minutes, turning once.
In a cast-iron skillet, heat remaining tablespoon olive oil over high until smoking. Remove steak from marinade; cook until browned, 4 to 5 minutes per side for medium-rare. Rest, covered, 5 minutes.
In a saucepan, bring marinade to a boil; strain into serving dish.
Slice steak against the grain: Place steak on a cutting board, and holding the blade of a sharp knife at a 45-degree angle, cut it into thin slices.
