Immersion Blender Method 

Put all of the ingredients into a wide-mouth pint size mason jar.

Place the immersion blender into the jar and blend all ingredients together into creamy white mayonnaise.

This takes less than 30 seconds.

Food Processor Method 

Place egg, lemon juice, mustard and salt into the food processor.

Cover with lid and turn the machine on high.

While the machine is running, drizzle in the oil through the hole at the top of the lid a little at a time at first.

Let the sauce begin to turn white and creamy then continue adding oil but not as slowly as at first.

Make sure the oil is thoroughly mixed into the sauce before turning the machine off.

Store in an airtight glass container and keep in the refrigerator.