By William Lander, Shaun Searley and Daniel Morgenthau
A classic, the QCH way. The quality of boquerones really matters here – get the best you can find.
Place the egg yolks, Dijon mustard, salt and vinegar in a blender and blend at the highest setting until the egg yolk starts to thicken.
Now begin to add the vegetable oil from a jug in a gentle, slow but steady stream.
Emulsify the oil and the egg yolks until thick and smooth, allowing yourself to add a few drops of water when necessary to prevent the mixture from splitting. On