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Dessert

Boiled Icing

A sugar icing made by boiling sugar, mixing into beaten egg whites, adding citric acid and vanilla, then beating until spreadable.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 5 ingredients
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Why it works: Sugar and vanilla are a kitchen classic. They rank in the top 8% of all ingredient pairs, and cooks put them together in 35,032 recipes. Both carry beta-damascenone, which smells apple, rose. The science ↓

Boiled Icing

Ingredients

Directions

Make the syrup

  1. In a saucepan, barely cover the sugar with water and boil until it hardens in water.

Whip and finish

  1. Slowly pour the hot sugar mixture into the beaten egg whites while beating continuously.

  2. Dissolve the citric acid in a few drops of hot water and add it along with the vanilla.

  3. Beat until cool and the icing reaches a spreadable consistency.

Recipe from a historical cookbook (Internet Archive).

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.

  1. Sugar + vanillatop 8% of all pairs
    Smell alikelow
    Cooked together35,032 recipes

    Shared aroma: beta-damascenone (apple, rose).

  2. Egg + sugartop 21% of all pairs
    Smell alikemoderate
    Cooked together122,807 recipes

    Shared aroma: 2-nonenal (fatty, green).

  3. Egg + vanillatop 23% of all pairs
    Smell alikelow
    Cooked together27,347 recipes

    Shared aroma: 1-octen-3-ol (mushroom, earthy).

Sugar and vanilla barely smell alike, yet cooks put them together in 35,032 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 whites
Whipped into a foam that gives the icing its light, airy structure.
Granulated sugar
Boiled into a syrup that sweetens the icing and sets into a glossy coating as it cools.
Citric acid
Adds a slight tang that balances sweetness and helps keep the egg white foam stable.

The step that matters

Pouring the hot syrup into the whites. The syrup must go in slowly while beating constantly. Pouring it in too fast can deflate the foam or leave streaks of cooked egg, while steady beating spreads the hot syrup evenly so the whites cook gently and hold their volume.

“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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