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 ↓
Onions Baked
Ingredients
Directions
The book says “a slow oven”. The 300°F (150°C) in the steps is the modern equivalent, not the book's own figure.
Prepare the onions
Wash the onions thoroughly but do not peel them.
Place the onions in a saucepan with slightly salted water and boil for 1 hour, adding more boiling water as needed.
Drain the onions and lay them on a cloth to dry.
Wrap each onion in buttered tissue paper, twisting the top to secure it.
Bake and serve
Bake the wrapped onions in a 300°F (150°C) oven for about 1 hour or until tender.
Peel the onions and place them in a deep dish.
Brown the onions slightly by basting with butter for 15 minutes.
Season with salt and pepper, and pour melted butter over them 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.
Photo for illustrative purposes only · Contact us to use it
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.
-
Onion + peppertop 11% of all pairsSmell alikemoderateCooked together68,474 recipes
Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
-
Onion + buttertop 15% of all pairsSmell alikemoderateCooked together42,912 recipes
Shared aroma: decanal (soap, orange peel).
-
Butter + peppertop 21% of all pairsSmell alikemoderateCooked together85,593 recipes
Shared aroma: trans-2-nonenal (cardboard, fatty).
Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs
What each ingredient does
- Spanish onions
- Become tender and sweet as they cook slowly in their skins.
- Butter
- Adds richness and helps the onions brown lightly while basting.
The step that matters
Brown the onions slightly by basting with butter for 15 minutes. Butter solids brown when heated, giving color and a nutty flavor. Basting keeps the surface moist so it browns evenly rather than drying or scorching.
Swap the onion
How well each one fits the dish's main ingredients (butter, pepper):
- Capsicumfits better
- Potatofits better
- Carrotfits about as well
- Onionthe original
Fit is the average pairing score against butter, 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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