Wash the fresh herbs thoroughly to remove any dirt.
Chop the parsley and cilantro finely.
Peel and mince the garlic cloves.
Add the chopped herbs to a mixing bowl with garlic.
Sprinkle in red pepper flakes, salt, and black pepper.
Pour in the red wine vinegar and lemon juice.
Drizzle in the olive oil while whisking to emulsify.
Taste and adjust seasoning as necessary.
Let the chimichurri sit for at least 30 minutes.
Serve fresh or store in the refrigerator for up to one week.