Flank Steak with Chimichurri and Shoestring Fries

Chimichurri turns up at nearly every Argentine grill in the Miami area, and it is the fastest way to make an affordable flank steak taste special. The sauce needs time more than skill; make it at least 30 minutes ahead so the garlic mellows and the vinegar draws flavor from the herbs. Use the flat-leaf parsley stems too, finely chopped, for more bite. Flank steak is lean and grainy, so sear it hot, stop at medium-rare, and slice it thin on a sharp angle.