Ah, the simple pleasure that is mayonnaise.
This creamy sauce will transform a dry sandwich, a bland and boring potato, or add that pop you need to a basic burger.
And the beauty of it is it has such a neutral flavour profile - pack it out with whatever flavourings you like - think spicy chipotle, smokey paprika, sweet roasted garlic, or the punch of fresh coriander and lime.
Getting technical here, mayonnaise is what's known as an emulsion sauce. An emulsion brings two seemingly un-bindable ingredients together (like oil and water). When you whisk together oil and water, they will come together for a brief moment as tiny droplets of oil suspended in water. But given the chance they will soon separate again. Enter the emulsifier - this acts as a binding agent between the two, coating each tiny microscopic droplet of oil, and helping it bind to its water counterpart and hold this structure even when the mixture settles. This is what thickens mayonnaise.
In regular mayonnaise, the emulsifier comes in the form of lecithin found in egg yolks. Here we substitute soy milk which is also naturally high in lecithin. Other non-dairy milks won't work, because they don't have this lecithin content, so be warned if you try this with your almond milk!
So, what do you need to know to make this technical sauce work? Thankfully, not much. Once you've done this once or twice, you can knock this up in 5 minutes flat.
The key is really just to whisk the milk quickly add the oil slowly - I'm talking a very slow drizzle - and whisk the milk as quickly as you can. Basically, you're trying to make the smallest possible droplets of oil within the milk. If you add the oil too quickly or whisk too slowly, the oil droplets will be too large and the sauce will 'split'! If you don't have a drizzle nozzle on your oil bottle, transfer into a jug, measuring cup or teapot(!) with a good spout - whatever works.
I like to use an electric whisk or immersion blender for the milk, as it moves faster than I possibly can with a hand whisk and makes this virtually impossible to fuck up. You can also do this in a blender or food processor, drizzling the oil in through the spout.
If you do go too quickly and your budding mayonnaise splits, it's not the end of the world. Transfer the split mixture into the jug/cup/teapot(!!!), clean out the bowl/blender thoroughly, add more soy milk, and start again but treating the split mixture as your oil, and going even slower this time! You might end up with a rather large batch, but it will work.
This mayo will keep happily in the fridge for a few weeks.