Why it works: Flour and butter 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-jelly Filling
Ingredients
Directions
Prepare
Grate the yellow zest from the lemons and squeeze out the juice.
Make the filling
In a bowl, mix the sugar and egg yolks, then add the egg whites and lemon juice.
Pour in the boiling water and stir in the flour mixed with the ½ cup of water.
Add the melted butter and cook until thickened.
Cool and use
Let it cool, then spread between layers of cake.
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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Flour + buttertop 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).
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 and whites thicken the filling as it cooks and give it body.
- Sugar
- Sweetens the filling and helps balance the tart lemon juice.
- Lemon juice
- Adds acidity and bright lemon flavor to the filling.
- Flour
- Thickens the filling so it sets to a spreadable consistency.
- Butter
- Adds richness and a smooth, silky texture to the filling.
The step that matters
Cooking until thickened. Egg and flour starches thicken as the mixture heats, but overcooking can curdle the eggs and leave a grainy texture. Cook gently and stop once it coats a spoon.
Swap the lemon
How well each one fits the dish's main ingredients (sugar, egg, flour, butter):
- Raisinfits better
- Vanillafits better
- Figfits about as well
- Lemonthe original
Fit is the average pairing score against sugar, 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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