Put enough water into a small pan so that it’s deep enough to cover an egg, and then bring the water to a boil.

While waiting for the water to heat, put the garlic, preserved lemon, vinegar, mustard, anchovies, Worcestershire sauce, and salt into a spice grinder or mini-processor, and buzz to mix well.

Drop the egg into the boiling water, then scoop it out with a small strainer after 40 seconds. Hold the strainer and egg under cold water until the egg is cool enough to handle, then crack the egg into the spice grinder. Buzz again.

With the food processor running*, slowly pour in the olive oil. After the olive oil is all in, keep running the processor until the dressing is fully emulsified.

My mini-processor: I've drilled a small hole through the plastic top of my spice grinder. A small enamel funnel fits tightly into this hole, so I can pour the olive oil in while the processor is running…and the dressing is emulsified perfectly. If you don't have a similar set up, transfer the dressing to a bowl and whisk like mad while pouring in the oil.