Place red wine vinegar, Dijon mustard, garlic and salt in a glass or metal container with a tight fitting lid and shake to combine. Add olive oil and shake vigorously, until dressing emulsifies and thickens to the consistency of cream.
Let dressing sit for 1 hour at room temperature before straining out garlic and serving. Dressing can be refrigerated, but should be brought to room temperature and shaken again before serving.
(Recipe courtesy Alton Brown)