Why it works: Onion and mustard match in chemistry and in kitchens. They rank in the top 6% of all ingredient pairs, and 9,259 recipes mention both. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Eggs a 'LA Robert
Ingredients
Directions
Prepare the sauce
Peel the onion and remove the heart.
Slice the heart and brown it in a saucepan with butter over medium heat.
Moisten with broth, season with salt and pepper, and reduce the sauce for about 10 minutes.
Finish and serve
Slice the hard boiled eggs and mix them into the sauce, heating gently for 2 minutes without boiling.
Add diluted mustard and serve.
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 aroma chemistry they share, and how many recipes mention both.
-
Onion + mustardtop 6% of all pairsAroma overlapstrongMentioned together9,259 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Pepper + mustardtop 9% of all pairsAroma overlapmoderateMentioned together15,430 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Onion + peppertop 11% of all pairsAroma overlapmoderateMentioned together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Onion + buttertop 15% of all pairsAroma overlapmoderateMentioned together42,912 recipes
Shared aroma: decanal (soap, orange peel).
-
Butter + eggtop 17% of all pairsAroma overlapmoderateMentioned together118,967 recipes
Shared aroma: decanal (soap, orange peel).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Onion
- Its heart is sliced and browned to build the savory base of the sauce.
- Butter
- Fat that browns the onion and carries flavor into the sauce.
- Lean broth
- Liquid that moistens the onion and reduces into a seasoned sauce.
- Hard boiled eggs
- Sliced and warmed in the sauce, providing the main body of the dish.
- Diluted mustard
- Adds a sharp, tangy note that brightens the rich sauce.
The step that matters
Heat the eggs gently without boiling. Once sliced eggs are added, boiling the sauce can toughen the egg whites and make the yolks grainy or rubbery, so keep the heat gentle.
Flavor stand-ins for the onion
How well each one fits the dish's main ingredients (butter, pepper, egg, mustard):
- Horseradishbetter flavor fit
- Chivebetter flavor fit
- Shallotbetter flavor fit
- Onionthe original
Fit is the average pairing score against butter, pepper, egg, mustard. Candidates are from the same food group and used in at least 100 recipes. This compares flavor only: it does not check the job the ingredient does in the dish (bulk, moisture, acidity, structure).
“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.
You might also like
Tomato Soup526 recipes
Brown Bread461 recipes
Mutton Broth292 recipes
Yorkshire Pudding264 recipesThe Sunday pairing: one pairing, the chemistry behind it, and how to cook it. No spam, unsubscribe anytime.
Prefer an account? Create a free account for sign-in; Pro adds the full results and chemistry.