Place the egg yolks in a large bowl or in a high container ( depending if you use an immersion blender or a regular egg beater). Add salt & pepper and vinegar.
Beat the egg yolks, then start adding the oil first drop by drop.While whisking, continue to add oil in a slow but steady stream, until is fully incorporated and you have a thick sauce. You may need to add more oil, so have a spare 2 fl oz on hand.
While whisking, add the lemon juice and whisk until combined. Adjust with salt and pepper to taste. Use straight away or refrigerate until ready to serve.
Mayonnaise can be stored in the fridge in an airtight container for a couple of days