Egg-Yolk Emulsion (Caesar & Mayonnaise)

What It Is

An emulsion is a stable suspension of two liquids that don't naturally mix — here oil dispersed as microscopic droplets through a water phase of lemon juice and Worcestershire. Egg yolk is the bridge: its lecithin coats each oil droplet so they can't coalesce. A Caesar dressing is essentially a flavoured mayonnaise carrying anchovy, garlic and hard cheese.

Why It Matters

Emulsified, the oil is divided into billions of tiny droplets that coat the tongue evenly and carry the fat-soluble aromatics across the whole palate at once. Split, you get a slick of oil and a separate hit of sharp acid arriving one after the other. The emulsion is also what lets the dressing cling to a leaf in a thin film instead of sliding to the bottom of the bowl.

How to Execute

• Build the water phase first: acid, mustard, Worcestershire, mashed anchovy and the yolk together. Mustard is a second emulsifier and cheap insurance.
• Steep the garlic in the acid ~10 min beforehand to tame its raw bite.
• Add oil slowly — drops at the start — whisking constantly until it thickens and pales. Once established, you can pour faster.
• Cut the oil ~50/50 with a neutral oil; all extra-virgin turns bitter under the shear of a blender.
• Finish with the grated cheese, then adjust with water a teaspoon at a time and balance salt and acid last.

Common Mistakes

• Adding oil too fast at the start — the most common split.
• All-EVOO under an immersion blender — bitter.
• Over-salting before the cheese and anchovy are in.