Why it works: Sugar and lemon are a kitchen classic. They rank in the top 18% of all ingredient pairs, and cooks put them together in 53,532 recipes. Both carry 2-nonenal, which smells fatty, green. The science ↓
Soft Icing
Ingredients
Directions
Make the icing
Beat the egg white until stiff.
Gradually add the powdered sugar and lemon juice or vanilla.
If the icing is too thin, add more sugar.
Apply
Have a cup of boiling water ready to dip a knife for smoothing.
Apply the icing to the cake while hot or the next day after baking.
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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Sugar + lemontop 18% of all pairsSmell alikelowCooked together53,532 recipes
Shared aroma: 2-nonenal (fatty, green).
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Egg + lemontop 19% of all pairsSmell alikelowCooked together44,316 recipes
Shared aroma: (e,e)-2,4-decadienal (fatty, deep fried).
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Egg + sugartop 21% of all pairsSmell alikemoderateCooked together122,807 recipes
Shared aroma: 2-nonenal (fatty, green).
Sugar and lemon barely smell alike, yet cooks put them together in 53,532 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 white
- Whipped into foam, it gives the icing its light, airy structure.
- Powdered sugar
- Dissolves into the whipped egg white to add sweetness and body.
- Lemon juice
- Adds a touch of acidity that brightens the sweetness and helps keep the icing stable.
The step that matters
Adding the powdered sugar. Sugar must be added gradually so the egg white foam stays stable. Adding it all at once can deflate the foam and leave the icing thin, which is why the recipe says to add more sugar if it is too thin.
Swap the lemon
How well each one fits the dish's main ingredients (egg, sugar):
- Vanillafits better
- Raisinfits about as well
- Lemonthe original
- Datesfits less well
Fit is the average pairing score against egg, sugar. 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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