Lemon Curd (Juice to Sugar to Egg to Butter, 1:1:1:1)

1 part (e.g. 100 g)

Fresh lemon juice — Strained; Meyer lemons give a softer, more floral curd

1 part (e.g. 100 g)

Caster (superfine) sugar — Fine-grain dissolves faster; granulated works if stirred off heat

1 part (e.g. 100 g, roughly 2 large eggs)

Whole eggs — Whole eggs give more body than yolks-only; yolks-only produces a richer, yellower curd

1 part (e.g. 100 g)

Unsalted butter — Cut into cubes and added off heat; higher-fat European butter (84%+) gives superior gloss

Whisk lemon juice, sugar, and eggs together in a heavy-bottomed saucepan or double boiler until sugar begins to dissolve. Cook over medium-low heat (or gentle steam), stirring constantly with a silicone spatula, until the mixture reaches 82–85°C (180–185°F) and coats the back of a spoon thickly. Remove from heat immediately. Add cold butter cubes gradually, stirring until each melts and emulsifies before adding the next. Strain through a fine-mesh sieve into a clean bowl. Press clingfilm directly onto the surface and refrigerate. The curd sets firmer as it chills, typically reaching spreadable consistency within 2 hours.

• Never exceed 85°C or the eggs will scramble; a probe thermometer is more reliable than timing alone.
• Adding butter off heat prevents overcooking and guarantees a smooth, glossy emulsion.
• Straining is non-negotiable: it catches any cooked egg threads and the lemon zest fibres if you used zested fruit.
• Lemon curd keeps refrigerated for up to 2 weeks; it can be frozen for 3 months with minimal texture change.
• A pinch of fine sea salt (0.5% of total weight) sharpens flavour and rounds sweetness without tasting salty.
• For a paler, more delicate colour, use white caster sugar rather than golden; for depth, a touch of lemon zest steeped in the juice for 10 minutes before cooking lifts the aroma markedly.

• Yolk-only curd

  Replace whole eggs with yolks only (same weight); richer, more golden, slightly less firm set

• Lime or yuzu curd

  Substitute lime or yuzu juice 1:1; tartness may require reducing sugar by 10–15%

• Reduced butter (3:3:3:2)

  Cutting butter to ¾ the weight of other components gives a lighter, less rich curd that sets marginally firmer

• Extra-rich curd (1:1:1:1.5)

  Increasing butter by half produces an ultra-glossy, very soft curd best used as a sauce or tart filling rather than a spread

• Passion fruit curd

  Replace half the lemon juice with strained passion fruit pulp; add a pinch of salt to balance tropical sweetness

• Pastry Cream (Milk to Egg Yolk to Sugar)

  Also an egg-thickened, custard-family preparation; stabilised with starch rather than butter emulsification

• Hollandaise (Butter to Egg Yolk)

  Same butter-emulsified-into-yolk principle; savory and warm-service rather than sweet and chilled

• Crème Brûlée (Cream to Egg Yolk)

  Shared egg-coagulation mechanism; cream replaces the citrus-acid element

1. 1.The Professional Pastry Chef — Bo Friberg
2. 2.Ratio: The Simple Codes Behind the Craft of Everyday Cooking — Michael Ruhlman
3. 3.The Complete Robuchon — Joël Robuchon
4. 4.How Baking Works: Exploring the Fundamentals of Baking Science — Paula Figoni

Confidence: high