Create a reduction: Peel and finely dice the shallot. Lightly crush the peppercorns with the blade of a large knife or in a mortar. Bring 6 tablespoons of water, vinegar, diced shallots and peppercorns to the boil in a small pot.
Boil down until the liquid is reduced to approx. 1⁄3. Pour reduction through a fine sieve into a metal bowl and allow to cool for approx. 10 minutes.
Clarify butter: To do this, melt the butter at low heat until it separates into three layers - an upper foam layer of egg white, a middle layer of yellow butterfat and the whey that settles at the bottom.
Skim off the top foam.
Then slowly pour the butterfat into a measuring cup so that the whey remains in the pot.
Mix the egg yolk with the reduction. Whisk in a hot water bath (60-70 °C) with a whisk until a thick, creamy foam is formed (approx. 3 minutes). The temperature should remain constant, as the sauce does not gain volume if the heat is too low.
Too much heat causes the sauce to curdle.
Beat clarified butter first drop by drop and then in a thin stream under the egg yolk mass. Season to taste with lemon juice, possibly Worcester sauce, salt and pepper.
Keep the sauce warm on a bain-marie and add other ingredients if necessary.
If the hollandaise thickens too much, stir in some warm water in a thin stream.