Custards, creams & meringues
Fruit Curd
A cooked custard of fruit purée or juice, sugar, eggs, and fat, thickened by controlled heat coagulation of proteins and stabilized by a hot emulsification of butter. A spreadable, glossy preserve-like component used as filling, sauce, or spread. Not to be confused with fresh fruit cream or uncooked fruit mixtures.
The formula
1000 g fruit purée : 1000 g sugar : 300–350 g whole egg + yolk : 1000 g butter
This 1:1:0.3–0.35:1 ratio by weight produces the classic thick, glossy curd. Scale by feel: fruit and sugar are held equal by weight; eggs total ~30–35% of fruit weight; butter equals fruit weight. Reduce sugar to 800–900 g for a softer set; increase to 1000–1100 g for a firmer, more stable preserve. For lemon curd (most common), substitute fruit purée with ~250 g lemon juice + zest and reduce sugar by 20–50 g.
Identity
- Uses whole eggs and yolks in combination — whites add water and structure, yolks add richness and emulsifying lecithin
- Butter is added off-heat in pieces and incorporated fully before cooling — this is what makes it a curd, not a custard
- Cooked to precisely 82–85 °C / 180–185 °F — below this proteins are under-coagulated and the curd won't thicken; above it eggs scramble irreversibly
- Sugar weight roughly equals fruit weight by mass — provides preservation, body, and lowering of the coagulation point
- Acid from the fruit (citrus juice, passionfruit, raspberry) is essential: it contributes flavor and helps set the curd by partially coagulating proteins
Ingredients
| Base | Fruit purée or juice (citrus juice + zest, berry, tropical) | Strained to remove seeds and coarse pulp for smooth texture. Concentrated purée yields a more intense curd. |
| Binder | Whole egg + egg yolk (combined) | Whole eggs provide structure and water; yolks provide richness, color, and emulsifying power from lecithin. Ratio of yolks to whole eggs affects richness and yellowness. |
| Seasoning | Sugar | Typically caster or granulated. Weight should roughly equal fruit purée weight for shelf-stable results; reduce to 60–80% for a tarter, softer set. |
| Fat | Unsalted butter, cold, cubed | Added off-heat in pieces. Fat provides richness, inhibits crystallization, and emulsifies the finished curd. Temperature of butter and speed of incorporation affect gloss. |
| Acid | Citric / tartaric acid (if fruit is low-acid) | Tartaric acid (cream of tartar) or lemon juice added to low-acid fruits like mango or strawberry to sharpen flavor and aid coagulation. Omit if using already acidic citrus or passionfruit. |
| Aromatics | Zest, vanilla, or spice | Lemon, lime, or orange zest; vanilla bean; a pinch of salt. Added at start with sugar to extract oils. |
Method
- 1Combine fruit purée, sugar, and any zest or aromatics in a heavy saucepan. Cook over medium heat, stirring, until sugar dissolves and mixture is hot (~60 °C).Dissolving sugar and heating the base before adding eggs prevents immediate scrambling and allows the mixture to come up to cooking temperature more uniformly.
- 2Whisk eggs and yolks together in a bowl. Gradually pour the hot fruit-sugar mixture over them while whisking constantly, starting very slowly to temper the eggs.Tempering the eggs prevents scrambling when hot liquid is introduced. Adding hot liquid to eggs gradually raises their temperature safely.
- 3Return the combined mixture to the clean saucepan. Cook over medium-low heat, stirring constantly with a wooden spoon or silicone spatula in a figure-eight pattern, until the curd reaches exactly 82–85 °C (180–185 °F) and coats the back of a spoon.82–85 °C is the window where egg proteins coagulate sufficiently to thicken without scrambling. The figure-eight motion ensures even heat distribution and prevents the bottom from scorching.
- 4Remove from heat immediately. Strain through a fine-mesh sieve if a perfectly smooth texture is required. Allow to cool to 60 °C, then add cold butter piece by piece, stirring until each piece is fully incorporated before adding the next.Straining removes any coagulated egg white threads. Butter is added at ~60 °C because it's warm enough to stay liquid and emulsify but cool enough not to cook the eggs further. Adding cold butter allows the emulsion to form gradually without breaking.
- 5Continue stirring occasionally as the curd cools to room temperature. Transfer to sterilized jars. Refrigerate until firm.Stirring while cooling prevents a skin from forming on top and ensures the emulsion remains uniform. Refrigeration completes the setting through fat solidification and further protein bonding.
Techniques that matter
Tempering eggs
Prevents protein scrambling when hot liquid is introduced; essential for any curd, custard, or sabayon base.
Controlled coagulation 75–85 °C
Egg protein coagulation is the primary thickener. The narrow temperature range is what separates a smooth curd from scrambled eggs.
Hot emulsification
Butter is incorporated into a warm (not boiling) base and acts as the continuous fat phase, trapping fruit solids and egg proteins — this is what gives curd its glossy, spreadable body.
Water-bath cooking (optional advanced method)
More gentle than direct heat; eliminates risk of scorching the bottom and gives precise temperature control for large batches.
Variations & derivatives
Lemon CurdEngland / Australia / New Zealand
The canonical form. 250 g lemon juice + zest : 250 g sugar : 2 whole eggs + 2 yolks : 250 g butter. Dense, tart, bright yellow.
Passionfruit CurdAustralia / New Zealand / South Africa
Very high natural acidity intensifies flavor; strained passionfruit pulp used at full strength. Darker, more complex, slightly gritty from seeds (seedless pulp available).
Orange CurdEngland / France
Uses blood orange or sweet orange juice. Lower acidity than lemon — often add a tablespoon of lemon juice or cream of tartar to sharpen set.
Raspberry / Strawberry CurdBroadly international
Made from cooked-down strained purée rather than fresh juice. Color is vivid; flavor is more delicate than citrus. Often benefits from a small amount of gelatin (1 leaf / ~2 g) to improve slice-ability as a filling.
Crème de Fruit (historical)19th-century French pastry
Ancestor of modern curd; used egg yolks, fruit syrup, and sugar but often lacked the butter emulsification. More of a thick fruit custard than a true modern curd.
Used in these dishes
Substitutions
- Whole egg + yolk combination → All whole eggs (fewer yolks) — Lighter color, less rich, slightly less emulsifying power; curd will be thinner and paler. Use 4–5 whole eggs per 250 g fruit purée.changes result
- Butter → Coconut oil or neutral plant fat — Dairy-free curd; will lack the richness and characteristic flavor. Add a pinch of salt to compensate. Texture will be slightly different.changes result
- Fruit juice + zest → Fruit purée (strained) — For berries and stone fruit: reduce purée slightly to account for lower acidity; may need 1 tsp lemon juice per 250 g to sharpen set.
- Sugar → Honey or invert sugar — Reduces setting temperature; honey adds flavor and darkens color. Reduce by ~15–20% and lower cooking temperature slightly.changes result
Troubleshooting
Curd is thin and won't set
Under-cooked (did not reach 82–85 °C), too much acid inhibiting coagulation, or insufficient egg for the amount of liquid → Return to pan, cook to 84 °C while stirring, or add 1–2 additional egg yolks and cook to temperature. Do not boil.
Curds or white streaks in finished curd
Egg proteins scrambled — temperature exceeded ~87 °C at any point, or butter was added when base was still too hot → Strain immediately through fine mesh; for slight scrambling, a brief blitz with an immersion blender can rescue texture. If severely scrambled, the batch is lost.
Grainy or gritty texture
Sugar not fully dissolved before cooking, or whole eggs curdled due to rapid temperature spike → Strain through fine sieve. Ensure sugar is fully dissolved at the start — cook the fruit-sugar base until it is clear and smooth before adding eggs.
Curd separates or weeps after refrigeration
Emulsion broken — butter was added too quickly or at too high a temperature, or the curd was frozen → Gently reheat to 50–55 °C, stir briskly to re-emulsify, then cool slowly with stirring. Do not freeze.