Why it works: Butter and flour are a kitchen classic. They rank in the top 12% of all ingredient pairs, and cooks put them together in 124,287 recipes. Both carry isobutyraldehyde, which smells malty, green. The science ↓
Lemon Pie
Ingredients
Directions
The book says “a moderately hot oven”. The 350°F (175°C) in the steps is the modern equivalent, not the book's own figure. The book gives no cooking times; the times in the steps were added in transcription, so check for doneness rather than trusting the clock.
Prepare
Preheat the oven to 350°F (175°C).
Grate the rind of the lemon and juice it.
Line a deep pie pan with a rich crust.
Make the filling
In a bowl, beat the egg yolks with the lemon rind and juice.
In another bowl, mix the sugar, butter, and flour thoroughly.
Pour the boiling water over the sugar mixture and stir until dissolved.
Add the egg yolk mixture to the dissolved sugar mixture.
Beat the egg whites until stiff peaks form and gently fold them into the mixture.
Bake
Pour the lemon mixture into the crust and bake for 30-35 minutes.
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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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Sugar + flourtop 15% of all pairsSmell alikemoderateCooked together92,116 recipes
Shared aroma: phenylacetaldehyde (hawthorne, honey).
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Egg + flourtop 15% of all pairsSmell alikelowCooked together106,462 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Lemon + buttertop 16% of all pairsSmell alikemoderateCooked together41,227 recipes
Shared aroma: 3-hexenal (apple, fruity).
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Lemon + flourtop 17% of all pairsSmell alikemoderateCooked together30,404 recipes
Shared aroma: isobutyraldehyde (malty, green).
Butter and flour barely smell alike, yet cooks put them together in 124,287 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
- Yolks add richness and body, while whipped whites lighten the filling and help it set.
- Sugar
- Sweetens the filling and dissolves into the hot water to form a smooth base.
- Flour
- Thickens the filling so it holds its shape when baked.
- Butter
- Adds fat for a richer, softer texture and flavor.
- Lemon
- Provides the acidity and aroma that define the pie's flavor.
The step that matters
Folding in the egg whites. Whipped whites hold air that lightens the filling; overmixing or stirring them in deflates the foam, leaving a denser pie.
Swap the lemon
How well each one fits the dish's main ingredients (egg, sugar, butter, flour):
- Raisinfits better
- Vanillafits better
- Figfits about as well
- Lemonthe original
Fit is the average pairing score against egg, sugar, butter, flour. 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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