Why it works: Lemon and walnut match in chemistry and in kitchens. They rank in the top 10% of all ingredient pairs, and cooks put them together in 2,149 recipes. Both carry 2-nonenal, which smells fatty, 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.
Make the filling
Dissolve cornstarch in a little cold water, then pour boiling water over it.
In a bowl, beat egg yolks, butter, sugar, flour, lemon juice, and grated lemon rind together until thick.
Assemble and bake
Pour the mixture into a pre-baked pie crust.
Beat egg whites with 1 teaspoon of sugar until stiff, then spread on top of the pie.
Bake in a 400°F (200°C) oven until light brown.
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 + walnuttop 10% of all pairsSmell alikestrongCooked together2,149 recipes
Shared aroma: 2-nonenal (fatty, green).
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Flour + buttertop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Flour + walnuttop 12% of all pairsSmell alikemoderateCooked together5,873 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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Walnut + buttertop 15% of all pairsSmell alikemoderateCooked together6,832 recipes
Shared aroma: eucalyptol (eucalyptus, herbal).
Flour and butter 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 thicken the filling, and whipped whites form a stiff topping that sets and browns.
- Cornstarch
- Thickens the filling as its starch swells in hot liquid, giving a sliceable set.
- Lemon
- Provides the sharp acidity and bright aroma that balance the sweetness.
- Sugar
- Sweetens the filling and helps stabilize the whipped egg white topping.
- Butter
- Adds richness and a smooth, velvety texture to the filling.
- Flour
- Adds extra thickening alongside the cornstarch for a firmer filling.
The step that matters
Dissolving the cornstarch. Cornstarch must be fully dispersed in cold water before the boiling water goes in, or it clumps. Starch granules thicken only when heated in liquid, so stirring keeps the filling smooth and evenly thickened.
Swap the walnut
How well each one fits the dish's main ingredients (sugar, lemon, egg, flour, butter):
- Almondfits better
- Pistachiofits better
- Milletfits better
- Walnutthe original
Fit is the average pairing score against sugar, lemon, egg, flour, 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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