Combine vinegar, salt, garlic and shallot in a medium bowl and let stand for 10 minutes. Stir in cilantro, parsley, and oregano. Using a fork, whisk in oil.
For steak: Separate sauce into equal parts. (Use half for basting or marinade; Use other half for table service). 拌牛油果: Avocado, parsley and cilantro, on crostini