The beef should be the choicest and freshest. You need to be sure of its quality. I buy it at the butcher, not the supermarket, as it is not known how much stored meat. Beef must be finely-finely chopped with a knife into small pieces. I love meat, coarsely ground in a meat grinder. So I have that.

Peel the onion, and also very finely chopped. Gherkins cut into small pieces. Add the onion and the gherkins to the meat.

Add the capers and mustard. I have two types of mustard - regular (very strong) and grain. You can vary the quantity of mustard according to your taste.

Add Worcestershire sauce and Tabasco. Tabasco is here essential, as it will add flavor and kill possible germs, if any. Pobrecito and salt to taste.

Pour in the olive oil and stir. At this stage you can break here the yolk and stir. I will be filing with the yolk on top, so I don't add immediately. Here you can taste and add more of something from the ingredients, if something is missing.