Why it works: Butter and flour are a kitchen classic. They rank in the top 12% of all ingredient pairs, and cooks put them together in 124,287 recipes. Both carry isobutyraldehyde, which smells malty, green. The science ↓
Mock Turtle Soup
Ingredients
Directions
Prepare the cat's head
Remove the brains from the cat's head, wash it thoroughly, and soak it in cold water for 1 hour.
Place the head in a stew-pan with 6 quarts of cold water and bring to a boil, skimming off any scum.
Simmer for 1.5 hours.
Remove the head and cut it into 1 to 1.5-inch pieces, including the tongue.
Store the pieces in a deep pan, covering them with some of the broth to prevent drying.
Make the broth
Add the bones and trimmings from the head and 4 pounds of knuckle of veal to the broth, cover, and boil gently for 4 to 5 hours.
Strain the soup into an earthenware pan.
Let it cool, stirring occasionally.
Remove the layer of fat from the top.
Place the clear jelly in a stew-pan, discarding the sediment.
Thicken the soup
Fry 6 ounces of sliced onions in 2 ounces of butter until light brown.
Stir in 6 ounces of flour.
Let it brown slightly.
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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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Onion + sagetop 12% of all pairsSmell alikemoderateCooked together3,628 recipes
Shared aroma: coumarin (sweet, hay).
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Sage + flourtop 13% of all pairsSmell alikemoderateCooked together2,115 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Veal + sagetop 14% of all pairsSmell alikelowCooked together670 recipes
Shared aroma: 3-hexenal (apple, fruity).
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Onion + buttertop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
Butter and flour barely smell alike, yet cooks put them together in 124,287 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
- Cat's head
- Provides the gelatinous body and rich flavor that form the soup's base.
- Knuckle of veal
- Adds gelatin and meaty depth to the broth during long simmering.
- Onions
- Browned with butter, they add sweetness and color to the thickening base.
- Butter
- Carries the onions' flavor and helps them brown into the roux.
- Flour
- Browned with the onion and butter, it thickens the soup.
The step that matters
Skimming and cooling the broth. Skimming scum during the first boil keeps the broth clear, and removing the fat after chilling prevents a greasy soup. Gentle simmering avoids clouding the liquid.
Swap the onion
How well each one fits the dish's main ingredients (veal, butter, sage, flour):
- Shallotfits better
- Leekfits better
- Chivefits better
- Onionthe original
Fit is the average pairing score against veal, butter, sage, 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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