Why it works: Onion and pepper are a kitchen classic. They rank in the top 11% of all ingredient pairs, and cooks put them together in 68,474 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓
Baked Onions
Ingredients
Directions
The book says “a quick oven”. The 400°F (200°C) in the steps is the modern equivalent, not the book's own figure.
Prepare the onions
Boil the onions in two waters, using salted boiling water for the second.
Drain the onions well and press them gently in a coarse cloth to remove excess water.
Place the onions side by side in a baking pan.
Bake and serve
Season with salt, pepper, and butter, then add the stock.
Bake in a 400°F (200°C) oven until browned.
Remove the onions and keep them warm in a deep dish.
Thicken the remaining gravy in the pan with browned flour.
Pour the gravy over the onions and return to the oven for 2 minutes before serving.
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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Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
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Butter + flourtop 12% of all pairsSmell alikelowCooked together124,287 recipes
Shared aroma: isobutyraldehyde (malty, green).
-
Onion + buttertop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
-
Onion + flourtop 17% of all pairsSmell alikemoderateCooked together32,460 recipes
Shared aroma: isobutyraldehyde (malty, green).
-
Pepper + flourtop 19% of all pairsSmell alikemoderateCooked together50,459 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
- Onions
- Provide the main body of the dish, becoming sweet and soft as they cook.
- Butter
- Adds fat and richness to the onions and the gravy.
- Browned flour
- Thickens the pan gravy so it coats the onions.
- Stock
- Forms the liquid that bakes with the onions and becomes the gravy.
The step that matters
Pressing the boiled onions dry. Excess water left on the onions dilutes the seasoning and the gravy and keeps the surface from browning well in the oven.
Swap the onion
How well each one fits the dish's main ingredients (pepper, butter, flour):
- Shallotfits better
- Chivefits better
- Capsicumfits better
- Onionthe original
Fit is the average pairing score against pepper, butter, 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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