Name: Stuffed Onions, American Style
Ingredients: 6 large onions; ½ cup fresh bread crumbs; 2 tablespoons fresh mushrooms, finely chopped; 2 tablespoons cooked fine herbs; ¼ cup Espagnole sauce; 2 tablespoons fresh parsley, finely chopped; coarse sea salt, to taste; black pepper, to taste; butter, for greasing and topping

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 ↓

Stuffed Onions, American Style

Oven, in the book's wordsA moderate oven

Ingredients

6 large onions
½ cup fresh bread crumbs
2 tablespoons fresh mushrooms, finely chopped
2 tablespoons cooked fine herbs
¼ cup Espagnole sauce
2 tablespoons fresh parsley, finely chopped
coarse sea salt, to taste
black pepper, to taste
butter, for greasing and topping

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

Prepare the onions by draining and cooling them.
Scoop out the center of each onion and chop it finely.
Mix the chopped onion with bread crumbs, mushrooms, fine herbs, Espagnole sauce, parsley, salt, and pepper until well combined.

Stuff and bake

Stuff the mixture into the onions.
Arrange the stuffed onions in a buttered flat saucepan.
Sprinkle bread crumbs over the top and place a small piece of butter on each onion.
Bake in a moderate oven at 350°F (175°C) until nicely browned.

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.

Parsley + peppertop 2% of all pairs

Smell alikestrong

Cooked together34,122 recipes

Shared aroma: 4'-methylacetophenone (bitter almond).
Bread + buttertop 7% of all pairs

Smell alikemoderate

Cooked together27,232 recipes

Shared aroma: delta-decalactone (sweet, creamy).
Mushroom + buttertop 7% of all pairs

Smell alikemoderate

Cooked together12,525 recipes

Shared aroma: trans-2-decenal (waxy, orange).
Onion + parsleytop 9% of all pairs

Smell alikemoderate

Cooked together25,843 recipes

Shared aroma: 2,4-decadienal (seaweed).
Bread + mushroomtop 10% of all pairs

Smell alikemoderate

Cooked together2,536 recipes

Shared aroma: 2-nonenal (fatty, green).

Ranks compare each pair with 20,000 random ingredient pairs on CompKitchen. How we score pairs

What each ingredient does

Onions: Form the edible shell that holds the stuffing and softens as it bakes.
Fresh bread crumbs: Absorb moisture and give the stuffing body, with more crumbs on top for browning.
Espagnole sauce: Adds savory depth and moisture to the stuffing.
Fresh mushrooms: Add earthy flavor and moisture to the filling.
Butter: Adds richness and helps the top brown in the oven.

Swap the onion

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

Shallotfits better
Capsicumfits better
Tomatofits better
Onionthe original

Fit is the average pairing score against bread, mushroom, sauce, parsley, pepper, butter. 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.