A little while ago a very clever (or perhaps very bored) person discovered that the liquid that surrounds tinned chickpeas and beans is full of protein and acts a lot like eggs in cooking. Don't ask me how they discovered it but bean water, when beaten, will turn into something that looks very much like meringue. They call it aquafaba (water + bean) and you can find heaps of recipes online that use it in everything from meringue to nougat. You can use the liquid from any tin of beans, but in my experience the lighter beans are best. Try to find beans with as little added salt as possible and definitely don't try to make meringue with baked beans because instead of soft peaks you'll just end up with a blender full of tomato sauce.
Here is our simplified and revisited version of the recipe...hence the name Mayonnaise and the Bean Water Miracle version 2.0.
All you have to do is drain the liquid from a tin of beans straight into your blender. We find chick peas the best.
Add about three tablespoons of apple cider vinegar
Then add a dash of sunflower oil (we've found sunflower oil gives us the best flavour), and start running the blender in short intervals, adding a little more oil each time. You really do have to go slowly, and it will start to emulsify and thicken.
Once it's getting thick, beware that one rotation of the blade too far can be enough to split the mixture and you'll end up with a gross watery/oily mess you don't know what to do with!
Once you've got it to the desired consistency add about a tablespoon of each of dijon mustard and wholegrain mustard and enough salt to season it nicely and stir that through.
It's not exactly low fat, but then foods that are packaged as low fat are usually so full of sugar and weird additives that you probably wouldn't want to eat that crap anyway.