Combine the egg, vinegar, lemon juice, mustard and salt in a food processor (or bowl) and process (or whisk) for 1-2 minutes until fluffy.
Add the oil in a very slow stream and continue to process (or whisk) the mixture until it becomes thick and creamy.
Store in the refrigerator for up to five days.
Servings 0
* Percent Daily Values are based on a 2,000 calorie diet. Your daily value may be higher or lower depending on your calorie needs.