Why it works: Parsley and pepper match in chemistry and in kitchens. They rank in the top 2% of all ingredient pairs, and cooks put them together in 34,122 recipes. Both carry 4'-methylacetophenone, which smells bitter almond. The science ↓
Baked Onion
Ingredients
Directions
The book says “a moderate oven”. The 350°F (175°C) in the steps is the modern equivalent, not the book's own figure.
Prepare the onions
Peel the onions.
Cook them in boiling salted water until tender.
Drain and chop.
Make the sauce
Melt the butter in a pan.
Add the flour and stir until smooth.
Season with salt and pepper.
Gradually add the stock or milk, stirring until it boils.
Add the chopped parsley and bread crumbs.
Boil for 8 minutes.
Finish and bake
Stir in the beaten egg and chopped onion.
Cool the mixture.
Fold in the stiffly beaten egg whites.
Pour into a buttered dish.
Bake for 20 minutes in a moderate oven at 350°F (175°C).
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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Parsley + peppertop 2% of all pairsSmell alikestrongCooked together34,122 recipes
Shared aroma: 4'-methylacetophenone (bitter almond).
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Bread + buttertop 7% of all pairsSmell alikemoderateCooked together27,232 recipes
Shared aroma: delta-decalactone (sweet, creamy).
-
Butter + milktop 7% of all pairsSmell alikemoderateCooked together81,283 recipes
Shared aroma: (z)-4-heptenal (biscuit, cream).
-
Bread + milktop 11% of all pairsSmell alikemoderateCooked together11,466 recipes
Shared aroma: 2-undecenal (sweet).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
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
- Eggs
- Whole beaten eggs bind the mixture, and whites folded in separately lighten it as it bakes.
- Butter
- Fat enriches the sauce base and adds flavour and a richer texture.
- Flour
- Cooked with butter, flour thickens the stock or milk into a smooth sauce that holds the mixture together.
- Stock or milk
- Liquid that, thickened with flour, forms the body of the sauce and moistens the dish.
- Bread crumbs
- Absorb liquid and add body, helping the mixture set into a soft, sliceable texture.
- Onions (in the method)
- Main vegetable, providing sweetness and savoury flavour once cooked tender.
The step that matters
Fold in the stiffly beaten egg whites. Whites trapped with air give lift during baking. Folding gently keeps the air in, while stirring hard would deflate the foam and leave the dish dense.
Swap the parsley
How well each one fits the dish's main ingredients (bread, butter, egg, flour, milk, pepper):
- Nutmegfits about as well
- Cinnamonfits about as well
- Parsleythe original
- Capersfits less well
Fit is the average pairing score against bread, butter, egg, flour, milk, pepper. 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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