Why it works: Sugar and flour are a kitchen classic. They rank in the top 15% of all ingredient pairs, and cooks put them together in 92,116 recipes. Both carry phenylacetaldehyde, which smells hawthorne, honey. The science ↓
Mocha Cake
Ingredients
Directions
The book says “a moderately hot oven”. The 350°F (175°C) in the steps is the modern equivalent, not the book's own figure.
Prepare
Preheat the oven to 350°F (175°C).
Grease a plain cake tin and line it with greased paper.
Sift the flour, baking powder, and potato flour or cornflour onto a piece of paper.
Make the batter
Cream the yolks of the eggs with the sugar for five minutes.
Whip the egg whites until stiff.
Mix half of the whipped egg whites with the yolk and sugar mixture.
Add the sifted flour mixture, then fold in the remaining egg whites gently.
Bake and cool
Pour the mixture into the tin and bake for about 35 minutes.
After 15 minutes, reduce the oven temperature slightly.
Once baked, turn the cake out and cool on a wire rack.
Ice and decorate
Once cool, split the cake in half and spread coffee butter icing on one half.
Press the other half on top, turn the cake upside down, and pour coffee glace icing over it.
Once set, decorate with remaining butter icing using a piping bag.
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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Sugar + flourtop 15% of all pairsSmell alikemoderateCooked together92,116 recipes
Shared aroma: phenylacetaldehyde (hawthorne, honey).
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Potato + flourtop 15% of all pairsSmell alikemoderateCooked together5,355 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Egg + flourtop 15% of all pairsSmell alikelowCooked together106,462 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Egg + sugartop 21% of all pairsSmell alikemoderateCooked together122,807 recipes
Shared aroma: 2-nonenal (fatty, green).
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Egg + potatotop 29% of all pairsSmell alikemoderateCooked together4,978 recipes
Shared aroma: (e)-2-octenal (fatty, green).
Egg and flour barely smell alike, yet cooks put them together in 106,462 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
- Eggs
- Whipped whites trap air and yolks add richness, giving the cake its structure and lift.
- Castor sugar
- Creamed with the yolks, it sweetens the cake and helps create a light, fine texture.
- Potato flour or cornflour
- Being starch rather than gluten-forming flour, it produces a tender, delicate crumb.
- Flour
- Provides the main structure that holds the light sponge together after baking.
- Baking powder
- Releases gas in the batter during baking, helping the cake rise.
The step that matters
Folding in the remaining egg whites gently. Whipped egg whites hold air that gives the cake its lift. Stirring vigorously knocks out this air, so the cake bakes up dense and flat instead of light.
Swap the potato
How well each one fits the dish's main ingredients (egg, sugar, flour):
- Arrowrootfits better
- Sweet potatofits better
- Shallotfits better
- Potatothe original
Fit is the average pairing score against egg, sugar, flour. 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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