1 cup fresh flat-leaf parsley, tightly packed (about 1 bunch of parsley)
1 cup fresh cilantro, tightly packed (about 1 bunch of cilantro)
1/2 cup diced red onion
3 Tablespoons fresh oregano, tightly packed (optional)
3 cloves of garlic, peeled
2 Tablespoons fresh lemon or lime juice
2 Tablespoons red wine vinegar
¼ tsp sea salt
¼ tsp freshly-ground black pepper
¼ tsp red pepper flakes, or more, to taste
½ cup good-quality olive oil
Add all ingredients except the olive oil to a food processor, and pulse a few times until chopped. Slowly stream in the olive oil, while pulsing the mixture a few more times until the olive oil is combined, and stopping to scrape down the sides of the food processor if needed.
Serve immediately, or refrigerate in a sealed container (this is the jar I used) for up to 3 days.