Step 1

Mix together the egg yolk, vinegar, and mustard in a bowl or in a food processor on low speed until combined and slightly frothy.

Step 2

Next, add in about ½ to 1 teaspoon of oil slowly while continuing to mix until it has been mixed in.

Step 3

Then, slowly pour in the oil while continuing to vigorously whisk by hand or at low speed in a food processor until all of the oil has been added and the mayonnaise has been emulsified and is thick.

Step 4

Finish by adding in lemon juice, or vinegar, and salt, and optional cayenne pepper.