You can whisk by hand, but easier done with a hand blender or in a food processor. All your ingredients need to be at room temperature to get the best results.
Beat the raw eggs for 20 seconds Add the mustard, vinegar, and salt and beat for another 20 seconds.
Slowly drizzle the oil, in drops at first for the first 1/2 cup beating as you go. Once incorporated you can increase the flow to a thin stream. Like magic the mixture will thicken and will emulsify.
Once thick, you can stop beating. Taste for seasoning and add more salt, vinegar or lemon juice to taste.
Pour into a jar with a lid and store in the fridge. I write the date on the side of the jar. It will keep for at least a week, but I have not had any issues storing it for a month.