In a medium heatproof bowl, combine dried oregano and red pepper flakes. Add boiling water and stir to combine. Let stand until oregano and pepper flakes have evenly absorbed water, 5 minutes.
Add parsley, garlic, and red wine vinegar and stir to combine. Stir in oil and season well with salt and pepper. Use right away or refrigerate until ready to use.
Can be done in a food processor too - do the parsley garlic and shallot (if using) first, then add the olive oil and vinegar
