Add the egg yolk, lemon juice, and mustard to a large bowl. Whisk until these ingredients are smooth.
add oil
Add a few drops of oil to the egg mixture and whisk to start the emulsion. Continue adding the oil a few drops at a time until the mixture thickens and turns lighter in color.
whisk
After you have a stable emulsion, you can start to add the oil in a thin stream as you continue to whisk.
store
Store mayonnaise in an airtight container in the fridge for up to two weeks.