The Preparation of Mayonnaise
[There are no pictures here. On purpose.]
Separate five eggs. Put the egg yolks into your food processor. Turn it on high. S.l.o.w.l.y drizzle in about 300ml-400ml of vegetable oil. The size of the yolks will make a difference, and it takes a little practice to know the breaking point. Yes, I’ve broken mayonnaise. It’s not a tragedy, it just meant I was rushing. Yes, I’ll be available for questions/panic attacks.
Anyway, now you should now have a food processor full of mayonnaise. Drizzle in some water. Don’t even bother with the salt. That’s it. Chill it and it’ll firm up. No really, that’s it.
If you’re going to use store-bought mayonnaise, assuming you find a mayonnaise that doesn’t have kitniyot in it, it’s going to have vinegar, stabilizers and other who-knows-what in it. We’re trying to stick to olive oil and eggs for cakes, so just follow the instructions above on how to make your own.