1. To make chimichurri, place parsley, cilantro, garlic, vinegar, 1/2 tsp salt, pepper flakes and black pepper in a food processor and pulse until finely chopped (see Options). Pour in the 1/2 cup olive oil and pulse to combine. Add a bit more oil if you find the chimichurri too thick. Transfer chimichurri to a medium bowl, mix in the avocado, cover and refrigerate until needed. It will keep for many hours in the refrigerator.

2. When ready to cook the steaks, take the avocado chimichurri out of the refrigerator. Pat steaks dry with paper towel; season with salt and pepper. Place oil in a very large, heavy skillet set over medium-high heat (see Options). When the oil is hot, add steaks to the skillet and pan-sear to the desired doneness, allowing about 3 minutes per side for rare, and 3 to 4 for medium rare. Plate the steaks, generously top with the avocado chimichurri, and serve.

Options: If you don’t have a food processor, you could finely chop the garlic, parsley and cilantro on a board. Now set them in a bowl and finish the chimichurri by mixing in the vinegar, salt, pepper flakes, oregano, pepper, oil and avocado. Instead of searing the steaks in a skillet, brush each one with 1 tsp oil and grill them, over medium-high heat, on a barbecue or indoor grill, to the desired doneness.