I love home made mayonnaise - so creamy and delicious. It isn't that hard to make (despite it's reputation) and the process is like magic - how the glossy and creamy mayo appears from yolks and oil! Plus it makes a great dairy-free butter substitute for my son (we have also been using hummus but I can't see that making a great egg salad).
1 egg yolk
6 fl oz oil (I used a light olive oil but any oil or fat will work - even lard)
1 tsp Dijon mustard
1/2 tbsp lemon juice
* 1 tsp whey or sauerkraut juice (optional)
Whisk or blend the egg yolk with a pinch of salt. Add a drop of oil and whisk/blend in. Once that is gone then add another drop. Keep adding oil - really slowly - for a few minutes. The mixture should be getting thicker. Add the mustard and lemon juice and whisk in. Then keep adding the oil. As you go on you can start adding the oil a little faster but be patient and don't rush things. If you do add the oil too quickly and the mixture curdles then don't panic. It can be fixed really easily. When no one is looking grab a clean bowl and a new yolk and slowly add the curdled mixture a drop at a time (like you were adding oil). It will come out just as normal. You can also get creative and add things like garlic, chopped herbs and spices to make flavoured mayonnaise's. They will keep for 3-4 weeks in the fridge.
* If you can tolerate dairy then you can also add a tsp of whey to the mixture. Then if you leave it to stand for 7 hours at room temp before refrigerating you get a probiotic mayonnaise which will be a little thicker and last longer. If dairy is a problem then you can substitute sauerkraut juice to the same effect.