Vinaigrette is an emulsion. Not quite like what Dulux offer to paint your walls with, but exactly the same scientific basis. Two nonmixable substances, such as oil and water, or in the case of a vinaigrette, oil and vinegar, are forced together. Shaking, whisking, beating, add kinetic energy to the mix which makes this happen.
Of course, they separate over time, which is why you need to add a stabiliser (otherwise known as an emulsifier or emulgent). In cuisine, the most common one is egg yolk, but don’t forget mustard either! These act by coating one of the elements of the emulsion and changing the chemical dynamics, essentially preventing them from separating.
That scientific basis should provide you the basic tools for making any vinaigrette or dressing that you see fit. The former, I would say is always oil and vinegar based and the latter, to me, would almost always be a stablised emulsion, so involving egg yolk. Strictly, a dressing means a sauce for a salad that includes vinaigrettes as a sub group, but I prefer my nomenclature!
To that end, I am going to explain how to make the two bases, essentially a basic vinaigrette and a mayonnaise. These can be adorned thereafter however you want; capers and gherkins in mayonnaise makes a tartar sauce. Add some garlic for aioli. Add mustard to the basic vinaigrette for a mustard vinaigrette, or even wasabi paste and soy sauce for an asian influenced dipping sauce! Essentially, the world is your oyster (and for them, incidentally, add a little finely diced shallot to a vinaigrette made with red wine vinegar).
1 part vinegar, 3 parts oil (say 1 tbsp vinegar, 3 tbsp olive oil), a pinch of salt and a pinch of sugar and a dash of lemon juice. Put it all into a clean jar (keep your marmalade empties), pop on the lid and shake until emulsified. Use immediately before it separates.
The choice of oil or vinegar is entirely up to you; extra virgin olive adds a great peppery bitterness, but this can be tempered by using half and half with say sunflower or groundnut oil. Personally, I wouldn’t use malt vinegar as it would be overpoweringly strong, but white wine, cider, red wine, rice wine vinegars all work nicely. As you get more advanced, you can start to substitute some of the vinegar for an acidic substance generally, such as citrus fruit juice. Use some rice wine vinegar and make up the difference with lime juice for an asian dressing.
Adding mustard and/or honey or even maple syrup will make an interesting sweet variant. All of the ingredients are cheap, for the quantities involved, and if you mess one up, it’s only a quick rinse of the jar before you can try again.
1 egg yolk to around 60-80 ml oil, pinch of salt, dash of lemon juice, splash of vinegar
Whisk the egg yolk and add the lemon juice, vinegar and salt. Then very slowly add the oil, whisking all the time. The amount is variable as it depends on what consistency you want and how large the egg yolk was. Eventually, it’ll all come together into mayonnaise. It will also be nothing like the shop-bought, which matches Dulux bright white, but will be quite yellow. This is good. Season it to taste and use as you see fit.
The choice of oil is subjective; personally, I use groundnut or sunflower and switch to extra virgin olive oil towards the end, otherwise it becomes overpoweringly bitter. Again, the choice of vinegar is also subjective. All this can be done in a food processor, which I would encourage if you want to add blue cheese for a blue cheese dressing (as it really helps break it up nicely), or other things that may take your fancy that would be very hard to whisk in, however, if you can bring yourself to do it in a bowl, it comes out better. There’s a reason for this, which has nothing to do with the food processor, but your psychology. If you add the oil to quickly, it’ll ruin the mayonnaise and I find that the food processor encourages me to add it too quickly. Maybe that’s just me though!
Anyway, once you have this base, you can add to it as you want! The world is again your oyster.