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
Sift the confectioner's sugar.
In a bowl, combine the egg white and water.
Add 4 tablespoons of the sifted sugar and stir until smooth.
Gradually add more sugar, stirring well until the icing is thick enough to spread on the cake.
Incorporate the lemon juice when the icing is partially made.
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 the protein structure that gives the icing body and a smooth, spreadable texture.
- Confectioner's sugar
- Supplies sweetness and bulk, thickening the liquid into a spreadable icing.
- Lemon juice
- Adds acidity that brightens the flavour and helps keep the icing stable.
The step that matters
Add the sugar gradually. Adding sugar too quickly makes the icing lumpy and hard to control, while adding it slowly lets you reach a smooth, spreadable thickness without overshooting into a stiff, dry icing.
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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