Why it works: Lemon and butter are a kitchen classic. They rank in the top 16% of all ingredient pairs, and cooks put them together in 41,227 recipes. Both carry 3-hexenal, which smells apple, fruity. The science ↓
Lemon Tarts
Ingredients
Directions
Prepare
Grate the yellow rind from the lemons and squeeze out the juice.
Make the custard
In a bowl, combine the grated rind, lemon juice, sugar, eggs, and butter. Beat the mixture well.
Place the bowl in boiling water and cook until it thickens to a custard, stirring frequently.
Fill and serve
Fill the pastry with the custard mixture.
Transcribed from a scanned cookbook and modernised for today's kitchens. Where the book gave no heat or time, or said "a moderate oven", the temperatures and times here may be modern equivalents rather than the book's own figures.
Explore the science
The flavor team
The pairs that carry this dish. Each one is judged two ways: how much their aromas overlap, and how often cooks already put them together.
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Lemon + buttertop 16% of all pairsSmell alikemoderateCooked together41,227 recipes
Shared aroma: 3-hexenal (apple, fruity).
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Egg + buttertop 17% of all pairsSmell alikemoderateCooked together118,967 recipes
Shared aroma: decanal (soap, orange peel).
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Sugar + buttertop 17% of all pairsSmell alikemoderateCooked together98,233 recipes
Shared aroma: guaiacol (smoky, sweet).
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Lemon + sugartop 18% of all pairsSmell alikelowCooked together53,532 recipes
Shared aroma: 2-nonenal (fatty, green).
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Lemon + eggtop 19% of all pairsSmell alikelowCooked together44,316 recipes
Shared aroma: (e,e)-2,4-decadienal (fatty, deep fried).
Lemon and sugar barely smell alike, yet cooks put them together in 53,532 recipes: they work on texture and structure more than aroma.
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Eggs
- Set the custard as they cook, giving it body and structure.
- Lemon juice
- Provides the sharp acidity that defines the tart's flavour.
- Sugar
- Sweetens the custard and balances the lemon's acidity.
- Butter
- Adds richness and a smooth, silky mouthfeel to the custard.
- Lemon rind
- Contributes concentrated aromatic lemon oils for fragrance and flavour.
The step that matters
Cook the custard over boiling water until it thickens. Egg proteins set gradually with gentle heat. Stirring frequently helps prevent lumps and curdling, so the custard thickens smoothly rather than scrambling.
Swap the lemon
How well each one fits the dish's main ingredients (sugar, egg, butter):
- Vanillafits better
- Lemonthe original
- Raisinfits about as well
- Figfits about as well
Fit is the average pairing score against sugar, egg, butter. Candidates are from the same food group and used in at least 100 recipes.
“What each ingredient does” and “The step that matters” were written by Claude from this recipe’s own method and reviewed in samples by CompKitchen.
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