Make the chimichurri sauce by combining the olive oil, vinegar, parsley, cilantro, garlic, red pepper flakes, lemon juice, and cumin in a food processor and blending until smooth. Season with salt and pepper, to taste. Place in an airtight container in the fridge until required.

In a small glass bowl, whisk the olive oil, lime juice, and chopped garlic with a fork. Season with salt and pepper, if desired.

Place the flank steak in a large, sealable plastic bag and add the olive oil mixture. Tightly seal the bag and turn a couple times to coat the steak in the marinade. Place in the refrigerator for at least 1 hour to overnight.

To prepare, heat the olive oil in a large skillet over medium-high heat. Remove the steak from the marinade and allow excess to drip off before adding to the hot skillet. Cook the steak for 3-4 minutes, then turn and cook for an additional 3-4 minutes for medium-rare results. Adjust cooking times to reach the desired level of doneness.

Remove from heat and transfer steak to a cutting surface. Let rest for 5 minutes before cutting into very thin slices against the grain.

To serve, drizzle steak with some Chimichurri sauce and pass remaining sauce for those who prefer a little more. Enjoy!