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
Make the icing
Place the egg white in a bowl and add lemon juice and a few drops of water.
Stir in powdered sugar until the mixture reaches a spreadable consistency.
If the icing becomes too stiff, add a few drops of water and stir again.
Color and flavor the icing as desired.
If the icing is prepared before the cake is ready, cover it with a wet cloth.
Ice the cake
While the cake is still warm, pile the icing in the center and smooth it over the top and sides with a wet knife.
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
- Provides protein that whips and sets into a smooth, glossy icing.
- Powdered sugar
- Adds sweetness and bulk, thickening the icing to a spreadable consistency.
- Lemon juice
- Adds acidity that brightens flavor and helps stabilize the egg white foam.
The step that matters
Adding water a few drops at a time. Too much liquid thins the icing and it will not hold its shape, while too little leaves it stiff and hard to spread. Adding water gradually lets you reach a spreadable texture.
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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