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Dessert

Rock Biscuits

Rock biscuits are almond and candied orange peel biscuits made with egg whites and powdered sugar.

From an old cookbook · modernised transcription
From a historical cookbook (Internet Archive) · 4 ingredients
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Why it works: Almond and orange are a kitchen classic. They rank in the top 6% of all ingredient pairs, and cooks put them together in 3,125 recipes. Both carry 2,4-decadienal, which smells seaweed. The science ↓

Rock Biscuits

Oven, in the book's wordsA slack oven

Ingredients

Directions

The book says “a slack oven”. The 300°F (150°C) in the steps is the modern equivalent, not the book's own figure.

Make the mixture

  1. In a pan, whisk the egg whites until they break.

  2. Add the sliced almonds, chopped candied orange peel, and powdered sugar to the egg whites.

  3. Mix well, adding more almonds and sugar if needed to bind the mixture.

Shape and bake

  1. Line iron plates with white wafer paper and place the mixture in biscuit shapes about the size of a half-crown piece, piled 1 to 1.5 inches high.

  2. Bake in a cool oven at 300°F (150°C) until lightly colored.

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. Almond + orangetop 6% of all pairs
    Smell alikemoderate
    Cooked together3,125 recipes

    Shared aroma: 2,4-decadienal (seaweed).

  2. Almond + sugartop 18% of all pairs
    Smell alikemoderate
    Cooked together15,679 recipes

    Shared aroma: 1-penten-3-one (fish, pungent).

  3. Orange + sugartop 20% of all pairs
    Smell alikelow
    Cooked together19,212 recipes

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

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

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

  5. Egg + almondtop 25% of all pairs
    Smell alikemoderate
    Cooked together12,645 recipes

    Shared aroma: 2,4-decadienal (seaweed).

Orange and sugar barely smell alike, yet cooks put them together in 19,212 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
Whisked to foam, they give the biscuits their light, airy structure and help bind the mixture.
Sweet almonds
Add body and a nutty texture, and their oils contribute to the biscuits' richness.
Candied orange peel
Adds moisture, chewiness, and bright citrus aroma and sweetness.
Powdered loaf sugar
Sweetens the biscuits and, being fine, dissolves into the egg whites to help bind the mixture.

The step that matters

Baking in a cool oven until lightly colored. Baking gently at a low temperature dries the meringue-like mixture and sets its shape without over-browning, which would make the biscuits darken and taste bitter.

Swap the orange

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

  1. Vanillafits better
  2. Raisinfits better
  3. Figfits better
  4. Orangethe original

Fit is the average pairing score against egg, almond, 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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