Directions

• In a glass bowl, whisk together egg yolk and dry ingredients.
• Combine lemon juice and vinegar in a separate bowl then thoroughly whisk half into the yolk mixture. Start whisking briskly, then start adding the oil a few drops at a time until the liquid seems to thicken and lighten a bit,
  (which means you’ve got an emulsion on your hands).
• Once you reach that point you can relax your arm a little (but just a little) and increase the oil flow to a constant (albeit thin) stream.
• Once half of the oil is in add the rest of the lemon juice mixture.
• Continue whisking until all of the oil is incorporated.
• Leave at room temperature for 1 to 2 hours then refrigerate for up to 1 week.