In Argentina, a small jar of deep-green chimichurri is often the first thing to greet you at your table.
1/2 cup chopped fresh flat-leaf parsley leaves
1 tablespoon chopped fresh oregano
1 teaspoon finely grated or minced garlic
1 1/2 teaspoons kosher salt
1 teaspoon freshly ground black pepper
1/2 teaspoon red pepper flakes
3/4 cup extra-virgin olive oil
1/3 cup red wine vinegar
In a medium bowl or jar, combine the parsley, oregano, garlic, salt, black pepper, and red pepper. Add the oil and vinegar* and mix well. Store covered for a couple of days and use before the herbs start to turn brown.
Make chimichurri up to 4 days in advance but do not add the vinegar as the acid will brown the green herbs. Bring it to room temperature and add the vinegar a few hours before serving.