In a medium bowl, combine the parsley, garlic, oregano, red pepper flakes, and red wine vinegar.
Add just enough olive oil to make a chunky sauce that's not too thick and not too runny.
Stir the ingredients until well blended.
Decant the sauce into the container of your choice and cover with a lid.
Let the chimichurri sit at room temperature overnight for the flavors to develop. The longer it sits out on the counter, the more the flavor intensifies. Refrigerate after 1 to 2 days. (The olive oil will congeal when chilled, but this doesn't affect the flavor or texture.) Bring the chimichurri to room temperature before using or serving.
