The Argentinean marinade enhances the flavor of beef while also adding some heat to make it more exciting. The steak is cooked quickly on high heat so that every part can be tender, juicy, and flavorful! The chimichurri sauce adds freshness with each bite making you forget all about your average steaks out there.
Using a food processor or blender, pulse the ingredients for the sauce just until everything is combined and garlic is very finely minced. Set aside.
Place the steak in a nonreactive (glass, ceramic, stainless steel) container. Spread four tablespoons of chimichurri sauce on top of it; flip over a few times to coat. Marinate at room temperature for 1 hour or in the refrigerator for at least 2 hours or overnight.
Allow meat to come to room temp before proceeding (about ½ hour out of the fridge); preheat grill to high (450 F). Sprinkle steak with salt and pepper and grill for 3-4 minutes per side (5-6 minutes per side), until it is lightly charred on the outside and medium-rare inside (or to your liking).
Let steak rest for 5 minutes before slicing. Slice against the grain. Spoon chimichurri on top or serve on the side.
Don't overprocess the sauce, as the oil will emulsify. The sauce is best when somewhat chunky.
The sauce is best served at room temperature and will keep for two days in the fridge.
Rest your flank steak for 5 minutes before serving, covering lightly with foil. The meat temperature will continue to rise about 5°F during this time (called "carryover cooking").
Always slice steak against the grain to keep it tender!
For the best results, read additional tips in the post above.
Nutrition information is approximate and meant as a guideline only.
How to check steak for doneness:
Use a meat thermometer - insert horizontally until the tip reaches the thickest part. Rare: 15°F (52°C); Medium rare: 135°F (57°C); Medium: 145°F (63°C); Medium well: 150°F (66°C); Well done: 160°F (71°C).
If you don't have a meat thermometer, use the touch test. Gently poke it with a blunt pair of tongs and then move away quickly:
The meat is rare if it's very soft but still tender enough to cut into without much effort.
If it's firmer but still soft, it's medium.
If there's no resistance, the steak is well-done.
To be on the safe side and not overcook the steak, check the inside temperature BEFORE you think your steak is ready.