Why it works: Lemon and sugar 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 Tarts
Ingredients
Directions
The book gives no oven temperature. The 350°F (175°C) in the steps was added when the recipe was transcribed, as a starting point.
Make the filling
Combine the grated rind and juice of one lemon, one cup of sugar, the yolk of one egg, and a large cup of cold water in a bowl.
Stir in 2 teaspoons of cornstarch and cook until it becomes a clear, straw-colored jelly.
Fill the pre-baked paste shells with the jelly.
Top and bake
Make a meringue by beating the egg white and adding 4 teaspoons of powdered sugar until stiff peaks form.
Cover the jelly with the meringue and bake in a 350°F (175°C) oven until lightly browned.
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 + 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).
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Sugar + eggtop 21% of all pairsSmell alikemoderateCooked together122,807 recipes
Shared aroma: 2-nonenal (fatty, green).
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
- Lemon
- Provides the rind and juice that give the filling its sharp, fragrant flavour.
- Sugar
- Sweetens the lemon filling and balances its acidity.
- Egg yolk
- Adds richness and helps thicken the filling as it sets.
- Cornstarch
- Thickens the lemon mixture into a clear, sliceable jelly when cooked.
- Egg white
- Whipped into a meringue that gives a light, airy, lightly browned topping.
- Powdered sugar
- Sweetens the meringue and helps it hold stiff, glossy peaks.
The step that matters
Cooking the cornstarch jelly. Cornstarch thickens only when the mixture reaches a simmer and is stirred, so it must cook until clear and thick before filling. Undercooked starch stays runny and the tart will not hold its set.
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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