Hollandaise versus mayonnaise.
It's asparagus season over here, and that means one or the other "fine" sauce.
I've made do with just butter, but this year I made a Hollandaise sauce. Here's the recipe:
150 g butter
3 egg yolks
2 tablespoons water or dry white wine
1-2 tablespoons lemon juice
white or cayenne pepper
Melt the butter, let cool.
Mix egg yolks with water or wine in a steel bowl in the top part of a waterbath. Whisk for a while, add some of the lemon juice. Take your bowl off the waterbath and add your liquid or very soft butter, whisking all the time, first drop by drop, then more and more at a time. You should end up with a smooth thickish sauce. (If you didn't, start with another egg yolk and pour your not-so-smooth mixture into that, whisking all the time, a drop at a time at first, then more and more at a time.) Add the rest of the ingredients, serve.
Now, a Bearnaise sauce is a Hollandaise with a few veggies and tarragon thrown in.
Compare that to your normal mayo:
2 egg yolks (I usually use the whites too - who really gives a hoot about all that egg yolk business?)
1-2 teaspoons vinegar or 2-3 teaspoons lemon juice
a smidgen of mustard
2 dl oil
Mix the egg yolks vinegar (or lemon juice) and the spices. Whisk for a few minutes. Add the oil, whisking all the while, first a drop at a time, then in larger and larger amounts, until all your oil is gone. You should end up with a smooth thickish mayo. (If you didn't, beat an egg yolk and whisk in your not-so-smooth mixture, first a drop at a time, then more and more in one go.) Serve.
As you can see, a Hollandaise sauce is a fancy mayo, made with butter and whipped on heat.
That being the case, whatever is in all those dried sauce packets at the supermarket? They can't have found out how to make butter powder ...