Stir. Combine chopped cilantro, parsley, shallot, garlic, oregano, chili flakes, and salt in a medium bowl. Stir in vinegar then slowly add olive oil while stirring until completely incorporated.

Serve. Dip a piece of bread into the sauce and taste it. Add more salt or vinegar or olive oil if needed. Spoon over grilled meats or soup or use as a marinade.