Why it works: Sugar and ketchup match in chemistry and in kitchens. They rank in the top 8% of all ingredient pairs, and cooks put them together in 260 recipes. Both carry ethanol, which smells alcoholic, ethereal. The science ↓
Rump Steaks and Onion Sauce
Ingredients
Directions
Fry the steaks
Fry the rump steaks until cooked to your liking.
Make the onion sauce
In a stewpan, heat the dripping over low heat and add the sliced onions and sugar.
Stir the onions until they are browned.
Gradually add the flour, then the broth (or hot water), along with salt and pepper.
Let the mixture boil gently until the onions are soft, then strain it through a sieve.
Finish and serve
Finely chop another large onion and add it to the stewpan with a little dripping. Stir until the onion is hot and nicely browned.
Add the strained sauce and ketchup, let it boil briefly, and serve with the steaks.
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 + ketchuptop 8% of all pairsSmell alikestrongCooked together260 recipes
Shared aroma: ethanol (alcoholic, ethereal).
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Flour + ketchuptop 13% of all pairsSmell alikemoderateCooked together2,435 recipes
Shared aroma: ethanol (alcoholic, ethereal).
-
Sugar + flourtop 15% of all pairsSmell alikemoderateCooked together92,116 recipes
Shared aroma: phenylacetaldehyde (hawthorne, honey).
-
Onion + flourtop 17% of all pairsSmell alikemoderateCooked together32,460 recipes
Shared aroma: isobutyraldehyde (malty, green).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Rump steaks
- The main protein, cooked by frying to the cook's preferred doneness.
- Onions
- Sweetened and browned to give the sauce its body and deep, savoury flavour.
- Flour
- Thickens the broth into a smooth sauce as it cooks.
- Broth
- Forms the liquid base of the sauce, adding savoury depth.
- Ketchup
- Adds sweetness and acidity to round out the sauce.
The step that matters
Browning the onions. Onions must be deeply browned, not just softened, because the browning reactions create the sauce's savoury colour and flavour. Pale onions yield a bland sauce.
Swap the onion
How well each one fits the dish's main ingredients (sugar, flour, pepper, ketchup):
- Capsicumfits better
- Arrowrootfits better
- Horseradishfits better
- Onionthe original
Fit is the average pairing score against sugar, flour, pepper, ketchup. 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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