Steak-frites, sauce béarnaise

As tradition built it

Serves 2. About 45 minutes.

Ingredients

For the béarnaise

• 100 ml white wine vinegar
• 2 banana shallots, finely chopped
• a small bunch (stems) tarragon stems and pepper
• 3 egg yolks
• 150 g clarified butter
• 1 tbsp each fresh tarragon and chervil, chopped

For the steak and frites

• 2 sirloin or rib-eye steaks
• 800 g floury potatoes, cut into batons

Method

1. Reduce the vinegar with the shallots, tarragon stems and pepper down to roughly 4 tablespoons of liquid.
2. Whisk the egg yolks into the warm reduction over very gentle heat, off direct flame if needed, until it forms a thick, aerated sabayon. Never let it scramble.
3. Off the heat, mount with the warm clarified butter in a thin stream, whisking constantly, exactly as a mayonnaise. Finish with the chopped tarragon and chervil.
4. Bring the steaks to room temperature, roughly 30 minutes to 1 hour depending on thickness. Season generously and cook to an internal temperature of 49 to 54°C for saignant. Rest, loosely covered, for a period roughly equal to the cooking time.
5. Double-fry the potatoes: first at 160°C until soft but not coloured, then at 180°C until crisp and golden, timed to finish while the steak rests.

What a modern chef changes

Sauce built by extraction rather than reduction, and a steak brought to temperature with total control

Rungs 2 and 3

Method

1. Cook the steak sous vide to precisely 52°C, then finish with a hard, fast sear on the Big Green Egg for real Maillard crust. This separates the two jobs the traditional pan tries to do at once, hitting an exact internal temperature and building a proper crust, and does both better than a single pan can.
2. Build the béarnaise reduction by freeze concentration instead of heat, after Yannick Alléno's own extraction technique: juice the shallot and tarragon aromatics, freeze, and let thaw over a sieve to collect a concentrated, unheated extract, then use this in place of the traditional simmered reduction for a cleaner, more purely aromatic base to the sabayon.
3. Hold the finished béarnaise in a warm water bath rather than serving it straight off the stove, which keeps the emulsion at serving temperature without continuing to cook it, the same logic bagna cauda's earthenware pot uses in the Italy volume of this atlas.