Why it works: Lemon and sugar 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 ↓
Royal Icing
Ingredients
Directions
Beat the egg white and 1 tablespoon of confectioners' sugar vigorously for 2 minutes.
Gradually add more confectioners' sugar by the tablespoon, beating well after each addition.
Continue adding sugar and beating until the mixture thickens and a knife makes a clean cut through it.
Add lemon juice a few drops at a time until you have used 1 tablespoon.
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 + sugartop 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).
Lemon and sugar 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 to foam, it traps air and gives the icing its structure as the sugar is beaten in.
- Confectioners' sugar
- Dissolves into the egg white to add sweetness and body, thickening the icing as more is added.
- Lemon juice
- Adds acidity that brightens the flavor and helps keep the icing stable.
The step that matters
Continue adding sugar until a knife leaves a clean cut. Adding sugar too quickly or stopping too early leaves the icing runny and unable to hold its shape. Beating well after each addition lets the sugar dissolve fully, so the icing thickens evenly and sets firm.
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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