To Make Traditional Egg Yolk Mayonnaise:

1 large egg yolk, save white for later use
3 teaspoons freshly squeezed lemon juice
1/4 teaspoon salt, plus more to taste
1/2 teaspoon smooth dijon mustard (not whole grain)
3/4 cup canola oil

To Make Egg White Mayonnaise:

1 large egg white, save yolk for later use
3 teaspoons freshly squeezed lemon juice
1/4 teaspoon salt, plus more to taste
1/4 teaspoon dry mustard (like Colman's)
1/2 cup canola oil

In this exact order, add the egg yolk (or egg white, if making the lowfat version), lemon juice, salt, mustard and oil to a cup. Let the ingredients sit for one minute, as the egg yolk settles to the bottom.

Place the immersion blender into the cup and starting slowly pulsing the mixture. In a few seconds you will see the mayo begin to form at the bottom. You can move the immersion lightly up and down to finish. The whole process should take no more than one minute. Scrape mayonnaise into a container; cover tightly and store in refrigerator for up to one week.