Name: Macaroni with Onions
Ingredients: 2 cups boiled macaroni; 2 cups boiled onions; 2 cups white sauce; ½ cup bread crumbs

Why it works: Onion and bread are a kitchen classic. They rank in the top 15% of all ingredient pairs, and cooks put them together in 8,676 recipes. Both carry 2,4-decadienal, which smells seaweed. The science ↓

Macaroni with Onions

Ingredients

2 cups boiled macaroni
2 cups boiled onions
2 cups white sauce
½ cup bread crumbs

Directions

The book gives no oven temperature. The 350°F (175°C) in the steps was added when the recipe was transcribed, as a starting point.

Prepare

Preheat the oven to 350°F (175°C).

Assemble and bake

In a baking dish, layer the boiled macaroni, boiled onions, and white sauce alternately.
Top with bread crumbs.
Bake until the top is brown.

Recipe from a historical cookbook (Internet Archive).

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.

Onion + breadtop 15% of all pairs

Smell alikemoderate

Cooked together8,676 recipes

Shared aroma: 2,4-decadienal (seaweed).
Onion + saucetop 19% of all pairs

Smell alikelow

Cooked together10,474 recipes

Shared aroma: ethanol (alcoholic, ethereal).
Sauce + breadtop 22% of all pairs

Smell alikelow

Cooked together4,934 recipes

Shared aroma: ethanol (alcoholic, ethereal).

Onion and sauce barely smell alike, yet cooks put them together in 10,474 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

Macaroni: Forms the bulk and body of the dish, holding its shape when baked.
Onions: Add sweetness and savory flavor that softens as the dish bakes.
White sauce: Supplies moisture and creaminess that binds the layers together.
Bread crumbs: Brown in the oven to create a crisp, golden top layer.

The step that matters

Bake until the top is brown. Browning on the surface comes from dry heat reacting with the crumbs, while the heat must also reach the centre to warm and set the sauce. Stopping too early leaves the dish pale and loose, and leaving it too long dries and toughens the crumbs.

Swap the onion

How well each one fits the dish's main ingredients (sauce, bread):

Tomatofits better
Shallotfits better
Capsicumfits better
Onionthe original

Fit is the average pairing score against sauce, bread. 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.

Brown Bread461 recipes

White Bread80 recipes

Bread Omelette60 recipes

Oatmeal Bread51 recipes

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Macaroni with Onions