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Dessert

Lemon Foam

A chilled lemon custard with folded egg whites.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 8 ingredients
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Lemon Foam

Why it works: Milk and vanilla are a kitchen classic. They rank in the top 5% of all ingredient pairs, and cooks put them together in 19,187 recipes. Both carry ethyl caproate, which smells fruity, apple peel. The science ↓

Lemon Foam

Ingredients

Directions

Make the lemon base

  1. Combine boiling water, lemon rind, lemon juice, sugar, and cornstarch (mixed with cold water) in a saucepan.

  2. Remove from heat and fold in the beaten egg whites until well combined.

Make the custard

  1. Heat milk in a saucepan and whisk in the egg yolks and vanilla until sweetened to taste.

  2. Bring the custard to a boil, then remove from heat and chill in the refrigerator.

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.

Photo for illustrative purposes only · Contact us to use it

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. Milk + vanillatop 5% of all pairs
    Smell alikemoderate
    Cooked together19,187 recipes

    Shared aroma: ethyl caproate (fruity, apple peel).

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

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

  3. Lemon + vanillatop 15% of all pairs
    Smell alikemoderate
    Cooked together5,961 recipes

    Shared aroma: eucalyptol (eucalyptus, herbal).

  4. Lemon + milktop 15% of all pairs
    Smell alikemoderate
    Cooked together19,053 recipes

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

  5. Lemon + sugartop 18% of all pairs
    Smell alikelow
    Cooked together53,532 recipes

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

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

Sugar
Sweetens the lemon base and balances the sharpness of the lemon juice.
Cornstarch
Thickens the lemon base as it heats, giving it body.
Egg whites
Folded in when beaten, they add airy lightness and foam structure.
Egg yolks
Enrich and thicken the milk custard, adding richness and a smooth texture.
Lemon juice
Provides the sharp acidity and bright citrus flavour.
Milk
Forms the liquid base of the custard, adding creaminess and body.

The step that matters

Bringing the custard to a boil. Cornstarch only thickens fully once it reaches a boil, so the custard must get hot enough. Egg yolks can scramble if the heat is too high or unstirred, so keep whisking while it heats.

Swap the lemon

How well each one fits the dish's main ingredients (sugar, egg, milk, vanilla):

  1. Figfits better
  2. Peachfits better
  3. Blueberryfits better
  4. Lemonthe original

Fit is the average pairing score against sugar, egg, milk, vanilla. 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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