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
Make the filling
Grate the rind of the lemons into a deep dish, then add sugar and flour (or corn-starch) and mix well.
Stir in the beaten egg yolks, lemon juice, water, and butter.
Cook in a double boiler until thickened, like cold honey.
Pour into a pie crust and bake until set.
Top and brown
Beat the egg whites with sugar until stiff.
Spread the meringue over the pie and return to the oven to brown slightly.
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
- Egg yolks
- Thicken the filling as they set and add richness to the custard.
- Flour
- Thickens the filling so it sets rather than running when cut.
- Sugar
- Sweetens the filling and helps stabilize the egg white meringue.
- Lemon juice
- Provides the sharp acidity that defines the filling's flavor.
- Egg whites
- Whip into a foam that forms the meringue topping and browns in the oven.
- Butter
- Adds fat for a smoother, richer texture in the filling.
The step that matters
Cook the filling in a double boiler until thickened. Egg yolks and starch thicken gently with indirect heat; too much heat can curdle the yolks or leave the filling grainy. The filling should be thick enough to set once cooled.
Swap the walnut
How well each one fits the dish's main ingredients (lemon, sugar, flour, egg, butter):
- Almondfits better
- Pistachiofits better
- Milletfits better
- Walnutthe original
Fit is the average pairing score against lemon, sugar, flour, egg, 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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