In the bowl of a food processor, add parsley, cilantro, red wine vinegar, red onion, garlic, salt, oregano, red pepper flakes, and black pepper. Pulse a few times until everything is roughly chopped.

While pulsing, slowly pour in olive oil until the sauce comes together, but avoid over-processing to keep a chunky texture.

Transfer chimichurri to a bowl, cover, and let it rest at room temperature for at least 2 hours to let the flavors meld.

Before serving, give it a quick stir. Adjust salt or vinegar to taste.

Spoon over grilled steak, roasted chicken, or vegetables. Enjoy!