Tartar Sauce

Method

1. Take the egg out of the fridge 20 minutes ahead — a cold yolk emulsifies badly. Chop your garnish first so the finished mayonnaise is not left standing: finely chop 20 g of drained cornichons, roughly chop 1 tsp of rinsed capers, and chop 1 tsp of shallot as finely as you can. Set aside on the board.
2. Put 1 egg yolk in a small, deep bowl with 1 tsp of Dijon mustard and a good pinch of fine sea salt. Whisk for 30 seconds until the mixture is smooth, pale and slightly sticky. Steady the bowl on a damp cloth so it cannot spin.
3. Begin adding 45 ml of sunflower oil literally drop by drop, whisking hard after each addition until it has disappeared. Once you have a thick, stable base — after roughly the first third of the oil — pour the rest in a very thin, steady stream, still whisking. The whole emulsion takes about 3 minutes and should end up firm enough to hold a peak on the whisk.