If using an immersion blender, add all ingredients to a tall cup or jar large enough at the base for the blender to fit with at least an inch of space around the blender.
Immerse the blender in the jar, using the blender to gently lift and stir while processing on high until the mayo is well mixed and creamy.
If using a food processor, add all ingredients except oil to food processor bowl and pulse to combine. Then, while the machine is running, slowly pour oil in a steady stream while processing until well mixed and creamy.
The mayonnaise will thicken even more when refrigerated. Use within one week.
Yield: 1 cup*Raw egg is not recommended for infants, the elderly, pregnant women, and people with weakened immune systems. To minimize the risk of salmonella, use pasteurized eggs available in some supermarkets or easily pasteurize eggs at home.Note: Although a food processor does a fine job, an immersion blender is ideal and foolproof as the ingredients can all go in together and no "slowly add the oil" is necessary.