Chop the parsley finely, add to a jar, preferably once with a lid to store in the fridge.
Add red wine vinegar, red pepper flakes, salt, oregano, olive oil and black pepper.
Mix well and store in the fridge for at least one hour. If the oil solidifies just stir it well and let it come to room temperature before serving.
Use in grilled meats, roasted veggies or as a marinade.