Anthony Bourdain's Steak Tartare

A sharp blade cuts through the muscle fibres cleanly. Most cells stay closed, so the water, the soluble protein and the myoglobin stay inside each piece. Each piece stays separate and red.

A food processor tears and crushes the meat. Many cell membranes break. The sarcoplasm, which is the liquid inside the muscle cell, comes out and coats the meat. The result is a wet, grey paste with no separate pieces.

Cut the beef last. Myoglobin on a new cut surface starts to oxidise to metmyoglobin, which is brown. Time between the cut and the plate is time for the colour to go.

Egg yolk and Dijon mustard are both emulsifiers. Yolk gives lecithin and lipoproteins. Mustard gives mucilage from the seed coat. Oil added slowly in a thin stream forms small droplets that these molecules hold in the water phase.

The emulsion coats each piece of beef with fat. This matters more with a lean cut such as fillet, which has little fat of its own.

The Cognac goes in after the emulsion is made. Ethanol dissolves aroma compounds that water cannot carry.