In a small saute pan, combine the vinegar with the water and minced shallot and cook on high heat until the liquid had reduced by 50%.
Strain the remaining vinegar into a medium-sized mixing bowl.
Add the egg yolks and a small pinch of salt, and whisk together vigorously for about 30 seconds.
Prepare a hot water bath, with a sauce or soup pot filled with simmering water that is the proper size to hold your medium-sized heatproof mixing bowl on top of it, without having the bottom of the mixing bowl touch the simmering water.
In a small sauce pot on the stove, add your clarified butter or regular whole butter and heat the contents until the butter is hot.
When the butter is hot, reduce the heat to the lowest setting.
After the egg yolk and vinegar have been whisked together aggressively, place the bowl over the hot water bath, and whisk continuously until the egg yolk mixture has roughly doubled in volume, or about 5 minutes.
*Try to avoid scrambling the eggs at this stage. They will scramble if they get too hot. If you notice your bowl getting too hot, simply remove the bowl from the hot water bath and whisk off the heat until the bowl begins to cool back down.
When the egg yolks have roughly doubled in volume over the hot water bath, very slowly drizzle the 6oz of hot melted butter into the egg yolk mixture while whisking continuously.
*Start by adding a very small stream of melted butter into the egg yolks while whisking, and wait until the hot melted butter is fully emulsified in the egg mixture before adding more.
When you have added the 6oz of butter and arrived at the desired Hollandaise sauce consistency, taste the mixture, and season with kosher salt.
If you prefer more acidity, add a squeeze of lemon juice or some more white wine vinegar here.
Now that your Hollandaise sauce is ready, keep the sauce in a small sauce pot, covered with plastic wrap, sitting in a bowl of hot water.
Alternatively, you can store the prepared Hollandaise sauce in a coffee thermos and try keeping it warm that way.
*Note that you don’t want the sauce to get too hot or too cold at this stage, as the emulsion will break.