Why it works: Sugar and lemon are a kitchen classic. They rank in the top 18% of all ingredient pairs, and cooks put them together in 53,532 recipes. Both carry 2-nonenal, which smells fatty, green. The science ↓
Lemon Filling
Ingredients
Directions
Make the filling
Combine sugar, water, lemon juice, and grated lemon rind in a small saucepan.
Place the saucepan in a larger pan of hot water.
Bring the saucepan to a boil.
Boil for 10 minutes.
Beat the eggs and stir them into the mixture until thick.
Assemble
Once cooled, spread the filling between layers of cake.
Ice the top with boiled icing or leave it plain.
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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Sugar + lemontop 18% of all pairsSmell alikelowCooked together53,532 recipes
Shared aroma: 2-nonenal (fatty, green).
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Egg + lemontop 19% of all pairsSmell alikelowCooked together44,316 recipes
Shared aroma: (e,e)-2,4-decadienal (fatty, deep fried).
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Sugar + eggtop 21% of all pairsSmell alikemoderateCooked together122,807 recipes
Shared aroma: 2-nonenal (fatty, green).
Sugar and lemon 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
- Thicken the filling as they set with heat, giving it body.
- Lemon
- Provides acidity and aroma from the juice and grated rind.
- Sugar
- Sweetens the filling and balances the lemon's tartness.
The step that matters
Stirring the eggs in. Eggs can scramble if they hit the hot mixture too quickly. Stir steadily while adding them so they thicken the filling smoothly instead of curdling.
Swap the lemon
How well each one fits the dish's main ingredients (sugar, egg):
- Vanillafits better
- Raisinfits about as well
- Lemonthe original
- Datesfits less well
Fit is the average pairing score against sugar, egg. 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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