In a sieve or colander, wash the rice thoroughly. Drain, and set aside.
In a large skillet or saucepan, heat 2 tablespoons of olive oil over medium heat.
Add the finely chopped onion and sauté until the onion becomes translucent - about 5 minutes. Add the garlic and sauté for 1 more minute, or until the garlic is fragrant.
Add the rinsed rice to the skillet and toast it for a 3 minutes, stirring frequently, until the rice grains are coated in the oil and slightly toasted.
Pour in the vegetable broth and bring it to a boil. Reduce the heat to low, cover the skillet, and let the rice simmer for about 15-20 minutes or until the liquid is absorbed and the rice is cooked. Remove from heat, take the lid off the pan, and cover it with a clean tea towel. Let it sit covered for 5 minutes.
In the meantime, prepare the chimichurri sauce. In the bowl of a food processor, combine the chopped parsley, cilantro, minced garlic, red wine vinegar, 2 tablespoons of olive oil, dried oregano, red pepper flakes, salt, and pepper. Blitz well until all the ingredients are evenly combined. Note: You could also use a bullet blender or simply chop the herbs finely with a sharp knife.
Once the rice has rested for 5 minutes, fluff it with a fork to separate the grains.
Pour the prepared chimichurri sauce over the cooked rice. Gently fold the sauce into the rice until it is evenly distributed.
Taste and adjust the seasoning as needed. Add more salt, pepper, or red pepper flakes according to your preference.
Serve chimichurri rice as a side dish, or as a base for your favorite protein or vegetables.