Place a heat-proof bowl over a pan of barely simmering water (the bottom of the bowl must NOT touch the water).
When the bowl is warm to the touch, pour in the egg yolks and lemon juice mixture, and start whisking them together immediately until lighter in color.
Transfer the egg yolk mixture to the bowl of the stand mixer (or any mixing bowl if using a hand mixer).
Start whisking the egg yolks over low speed.
Turn up the speed to medium and start drizzing in the butter, a few drops at a time at the start.
When the mixture starts to thicken, turn up the speed to high and pour the melted butter in a very thin stream.
Continue whisking until the mixture is fully emulsified. To test, scoop with a spoon and allow to drip back into the bowl. If the liquid falls in ribbons, it is done.
Taste the Hollandaise sauce and add as much salt as your taste buds require.