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 gives no oven temperature. The 400°F (200°C) in the steps was added when the recipe was transcribed, as a starting point.
Prepare the crust
Preheat the oven to 400°F (200°C).
Line a pie dish with crust and bake until golden brown.
Make the filling
In a bowl, mix together sugar, butter, egg yolks, lemon juice, and lemon rind.
Place the mixture on the stove and add boiling water.
Once it boils, stir in flour dissolved in cold water.
Cook until thickened, then pour into the baked crust.
Top and brown
Beat the egg whites until stiff, then spread over the pie.
Return the pie to the oven to brown the meringue.
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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Butter + lemontop 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
- Flour
- Thickens the lemon filling as it cooks with the boiling water.
- Egg yolks
- Add richness and help thicken the filling as it sets.
- Egg whites
- Whipped into a stiff foam that forms the meringue topping.
- Sugar
- Sweetens the filling and balances the sharpness of the lemon.
- Lemon juice
- Provides the sharp, acidic flavour that defines the pie.
The step that matters
Cook until thickened, then pour into the baked crust.. Flour needs to boil fully to thicken the filling; undercooked starch leaves it runny. The filling should be hot when poured so the crust is not soggy and the pie sets properly.
Swap the lemon
How well each one fits the dish's main ingredients (sugar, butter, egg, flour):
- Raisinfits better
- Vanillafits better
- Figfits about as well
- Lemonthe original
Fit is the average pairing score against sugar, butter, egg, 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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