Hollandaise Sauce

Allow about 8 minutes for setup, measuring, egg separation and clean-up. Have the separately prepared accompaniments ready to serve before starting the sauce. Check that a 20–22cm curved heatproof mixing bowl sits securely over a 16–18cm saucepan without its base touching the water; add roughly 3cm water to the pan, adjusting for that clearance. Keep both vessels off the heat for now. Measure all the ingredients, including the salt allowance using fine scales if available, keeping 10ml lemon juice with the base water and 5ml lemon juice for finishing. Keep the 10ml correction water separate. Cut the butter into roughly 1cm pieces. Use only large hen eggs with a British Lion mark or Laid in Britain assurance that you can verify. Separate two yolks into the bowl without letting shell fall in; the whites are not part of this sauce. Wash hands and clean surfaces and utensils after shell/raw-egg handling. Do not wash eggs. Whisk the yolks with 15ml cold drinking water, all 5ml vinegar and the 10ml base lemon juice until combined.

Allow about 6 minutes for these overlapping jobs. Bring the saucepan bath to a bare simmer over medium heat, then turn the hob low: occasional small bubbles and light steam, not a rolling boil. At the start of this stage fill the heatproof pouring jug with hot tap water and leave it to warm for about 4 minutes while all 140g butter melts in its separate pan over the lowest heat. Stir the butter and lift the pan off as soon as no solid pieces remain, allowing about 4 minutes; do not brown, boil, skim or discard the milky liquid. During the remaining 2 minutes, empty the jug completely and dry its inside and lip with a clean cloth. Stir and scrape every part of the whole melted butter into this warmed jug. Fill the second heatproof bowl with fresh hot tap water and stand the jug securely in it, with the water below the jug lip so none enters the butter. Keep this jug bath off the hob. This is brief temperature control during making, not a holding method for finished sauce. The butter should be fully fluid and the outside of the jug at butter level comfortably warm to a brief touch, not painfully hot; the butter must not steam or sizzle. If the jug feels cool, replace its surrounding water with fresh hot tap water and stir until warm before starting the yolks. Watch both pans during heat-up; if needed allow longer for the simmer and warm melted butter.

Set the mixing bowl over the barely simmering saucepan bath and whisk continuously for about 4 minutes, sweeping the curved base and sides. Keep the bowl clear of the water. The butter jug stays in its off-hob hot-water bowl during this stage; no second hob or extra whisking task is needed. The yolks should become paler and foamy, then form a light ribbon that briefly shows when the whisk is lifted. The bowl and base should still be warm, not merely thickened and left to cool. Do not aim for a stiff paste. If the mixture catches at the edges, lift the bowl clear and keep whisking off the bath, allowing longer if needed to reach the cue. Remove onto the folded dry tea towel when ready. Immediately check that the butter is still fully liquid and its jug comfortably warm, without steam. If it has cooled, leave the yolk bowl off the heat, replace the water around the jug with fresh hot tap water and stir the butter until warm. If the base has cooled during this adjustment, briefly return it to the barely simmering bath, whisking continuously just until warm and flowing again; lift off at once if it starts catching. Count this extra adjustment time rather than leaving a cold base for pouring. Turn off the saucepan hob and start the butter addition straight away. These are culinary heat controls, not pasteurisation.

Allow about 5 minutes off the heat to incorporate all the warm melted butter, whisking without stopping. Leave the jug standing in its off-hob hot-water bowl between pours so it does not cool in a cold jug. Stir the jug to redistribute its milky liquid before the first pour. Begin with drops, whisking each addition in until the base looks uniform, then move to a very thin trickle once it is clearly thickening smoothly. Pause pouring whenever butter is visible on the surface and whisk it in before continuing. Scrape in every bit of the liquid and solids too. The sauce should be glossy and cohesive, with no oily puddles. If the butter jug becomes cool or the butter thickens, pause pouring, replace the surrounding water with fresh hot tap water and stir until the butter is comfortably warm and fully liquid again; do not add cool butter or lumps. Allow extra time for this adjustment. Do not put the emulsion back over heat during incorporation or reheat the finished sauce. The warm base, warm butter and warmed pouring jug reduce heat loss; finish and serve without delay.

Allow about 2 minutes for finishing and serving. Whisk in the reserved 5ml lemon juice, the pinch of white pepper and an initial 0.5g fine salt weighed on fine scales, or a scant 1/8 tsp if fine scales are unavailable. Taste with a clean spoon, then add a little more salt only if needed, staying within the 1g allowance; do not automatically add all the reserved salt. The sauce should fall in a broad flowing ribbon and coat a spoon, rather than sit like mayonnaise. Only if too thick, whisk in 5ml of the reserved cold drinking water, then the remaining 5ml only if still needed; do not add unused water automatically. Spoon directly over the ready accompaniments on serving plates rather than cooling this small batch in another jug, and serve straight away. There is no planned keeping-warm, resting, chilling, freezing or reheating route for finished sauce. If it becomes grainy or separates into oil and yolk, this untested method does not promise a rescue; do not serve it as smooth hollandaise.