Why it works: Lemon and pepper match in chemistry and in kitchens. They rank in the top 3% of all ingredient pairs, and cooks put them together in 27,047 recipes. Both carry trans-2-nonenal, which smells cardboard, fatty. The science ↓
Sauce Robert
Ingredients
Directions
Make the sauce
Melt the butter in a saucepan.
Fry the onions until brown, being careful not to burn them.
Add the flour and shake the onions in it, then fry for a few more minutes.
Stir in the stock and seasonings, then boil gently for 10 minutes.
Skim the sauce.
Add the mustard, vinegar, and lemon juice, then boil once more.
Serve
Serve with steak, pork chops, liver, goose, turkey, etc.
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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Lemon + peppertop 3% of all pairsSmell alikestrongCooked together27,047 recipes
Shared aroma: trans-2-nonenal (cardboard, fatty).
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Onion + mustardtop 6% of all pairsSmell alikestrongCooked together9,259 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Mustard + vinegartop 7% of all pairsSmell alikemoderateCooked together14,067 recipes
Shared aroma: isobutyraldehyde (malty, green).
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Pepper + mustardtop 9% of all pairsSmell alikemoderateCooked together15,430 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Lemon + mustardtop 11% of all pairsSmell alikestrongCooked together3,816 recipes
Shared aroma: eucalyptol (eucalyptus, herbal).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Flour
- Thickens the sauce as it cooks with the butter and onion juices.
- Onions
- Browned slowly, they add deep savory sweetness and flavor to the sauce.
- Butter
- Carries the frying of the onions and adds rich flavor and fat to the sauce.
- Vinegar
- Adds acidity that sharpens the sauce and balances its richness.
- Mustard
- Adds sharp, pungent flavor that complements the browned onions and meat.
The step that matters
Fry the onions until brown, without burning them. Browning builds the sauce's deep flavor through caramelization, but burnt onions turn bitter and spoil the whole sauce.
Swap the lemon
How well each one fits the dish's main ingredients (butter, pepper, onion, mustard, vinegar, flour):
- Avocadofits better
- Limefits better
- Lemonthe original
- Mangofits about as well
Fit is the average pairing score against butter, pepper, onion, mustard, vinegar, 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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