Name: Potato Pie
Ingredients: 1 pound potatoes, peeled and thinly sliced; ¾ ounce onion, chopped; ¼ teaspoon pepper; ¼ teaspoon salt; ½ cup water; 2 ounces fresh butter, cut into small pieces; puff pastry (enough to cover the pie dish); optional: yolks of 4 hard-boiled eggs; optional: 1 tablespoon mushroom ketchup

Why it works: Potato and onion are a kitchen classic. They rank in the top 3% of all ingredient pairs, and cooks put them together in 9,023 recipes. Both carry 2-isopropyl-3-methoxypyrazine, which smells earthy, pea. The science ↓

Potato Pie

Ingredients

1 pound potatoes, peeled and thinly sliced
¾ ounce onion, chopped
¼ teaspoon pepper
¼ teaspoon salt
½ cup water
2 ounces fresh butter, cut into small pieces
puff pastry (enough to cover the pie dish)
optional: yolks of 4 hard-boiled eggs
optional: 1 tablespoon mushroom ketchup

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 the pie

Layer the sliced potatoes in a pie dish, adding chopped onion, pepper, and salt between each layer.
Pour in the water and dot the top with pieces of butter.
Cover the pie with puff pastry and seal the edges.

Bake and serve

Bake for about 1.5 hours.
If desired, add the yolks of hard-boiled eggs and pour in mushroom ketchup through a funnel before serving.

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.

Potato + oniontop 3% of all pairs

Smell alikemoderate

Cooked together9,023 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Butter + mushroomtop 7% of all pairs

Smell alikemoderate

Cooked together12,525 recipes

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

Smell alikemoderate

Cooked together8,305 recipes

Shared aroma: 2-isopropyl-3-methoxypyrazine (earthy, pea).
Potato + mushroomtop 9% of all pairs

Smell alikestrong

Cooked together968 recipes

Shared aroma: 1-octen-3-one (mushroom, metallic).
Onion + mushroomtop 10% of all pairs

Smell alikemoderate

Cooked together10,626 recipes

Shared aroma: 2,4-decadienal (seaweed).

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

What each ingredient does

Potatoes: Form the bulk of the pie and soften into a tender filling as they bake.
Butter: Adds richness and moisture, melting over the potatoes as the pie bakes.
Puff pastry: Encloses the filling and bakes into a crisp, flaky, browned top.
Onion: Adds savory flavor that deepens as it cooks with the potatoes.

Swap the onion

How well each one fits the dish's main ingredients (potato, pepper, butter, egg, mushroom, ketchup):

Capsicumfits better
Chivefits better
Asparagusfits about as well
Onionthe original

Fit is the average pairing score against potato, pepper, butter, egg, mushroom, ketchup. 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.